49320275 0 Adams Basic Training and Examples b5

MSC.ADAMS BASIC TRAINING and EXAMPLES

Chen Ke Liang Jihui

SHENYANG LIGONG UNIVERSITY

2007

CONTENTS

2

ADAMS BASIC TRAINING and EXAMPLES

I


CONTENTS

SectionⅠ- ADAMS/View

1 ADAMS/View Basics ........................................................................................ 1

1.1 Introducing ADAMS/View ....................................................................................... 1

1.1.1 Steps in Modeling and Simulating .................................................................... 1

1.1.2 Build Your Model .............................................................................................. 1

1.1.3 Test and Validate Your Model .......................................................................... 3

1.1.4 Refine Your Model and Iterate .......................................................................... 5

1.1.5 Customize and Automate ADAMS/View......................................................... 5

1.2 Working with the ADAMS/View ............................................................................. 6

1.2.1 Starting ADAMS/View ...................................................................................... 6

1.2.2 ADAMS/View Main Window ........................................................................... 6

1.2.3 Starting a New Modeling Session ..................................................................... 7

1.3 Defining the Modeling Environment ........................................................................ 9

1.3.1 Specifying the Type of Coordinate System ...................................................... 9

1.3.2 Setting Units of Measurement ......................................................................... 10

1.3.3 Specifying Gravitational Force ........................................................................ 11

1.3.4 Specifying Working Directory ........................................................................ 12

2 Building Models in ADAMS/View ................................................................. 13

2.1 Creating Parts .......................................................................................................... 13

2.1.1 Creating Construction Geometry..................................................................... 14

2.1.2 Creating Solid Geometry ................................................................................. 19

2.1.3 Creating Complex Geometry ........................................................................... 23

CONTENTS

II

2.1.4 Adding Features to Geometry ......................................................................... 25

2.1.5 Working with Point Masses ............................................................................. 26

2.2 Modifying Parts ...................................................................................................... 26

2.2.1 Modifying Rigid Body Geometry ................................................................... 26

2.2.2 Modifying Part Properties ................................................................................ 27

2.3 About Constraining Your Model ............................................................................ 27

2.3.1 Types of Constraints ........................................................................................ 27

2.3.2 Accessing the Constraint Creation Tools ........................................................ 27

2.3.3 Working with Joints ......................................................................................... 28

2.4 Applying Forces to Your Model ............................................................................. 37

2.4.1 Accessing the Force Tools ............................................................................... 37

2.4.2 Constructing Applied Forces ........................................................................... 38

2.4.3 Constructing Flexible Connectors ................................................................... 41

3 Simulating Models in ADAMS/View ............................................................. 43

3.1 Types of Simulations .............................................................................................. 43

3.2 Accessing the Simulation Controls ......................................................................... 44

3.3 Performing an Interactive Simulation ..................................................................... 45

3.4 Viewing and Controlling Animations ..................................................................... 46

3.4.1 About Animating Your Simulation Results .................................................... 46

3.4.2 Accessing the Animation Controls .................................................................. 47

3.4.3 Playing Animations .......................................................................................... 47

4 Examples ......................................................................................................... 49

4.1 The Latch Design Problem ..................................................................................... 49

4.1.1 Introducing the Latch Design Problem ........................................................... 49

4.1.2 Building Model ................................................................................................. 50

4.1.3 Testing Your First Prototype ........................................................................... 55

4.1.4 Validating Results Against Physical Test Data .............................................. 59

4.1.5 Refining Your Design ...................................................................................... 62

4.1.6 Iterating Your Design ....................................................................................... 63

4.1.7 Optimizing Your Design .................................................................................. 66

4.2 The Front Suspension Design Problem ................................................................... 70

4.2.1 Introducing the Front Suspension Design Problem ....................................... 70

4.2.2 Building Model ................................................................................................. 71


III

4.2.3 Testing the Front Suspension .......................................................................... 76

4.3 The Full Vehicle Design Problem ........................................................................... 83

4.3.1 Creating Chassis Model ................................................................................... 83

4.3.2 Creating Front Suspension Model ................................................................... 85

4.3.3 Creating Steering System Model ..................................................................... 88

4.3.4 Creating Rear Suspension Model .................................................................... 92

4.3.5 Creating Tire and Road .................................................................................... 83

4.3.6 Testing the Full Vehicle ................................................................................. 101

Section II - ADAMS/Car

5 Introduce ADAMS/Car .................................................................................. 106

5.1 What is ADAMS/Car? .......................................................................................... 106

5.2 What You Can Do with ADAMS/Car .................................................................. 107

5.3 How You Benefit from Using ADAMS/Car ......................................................... 108

6 Introducing Analyses in ADAMS/Car .......................................................... 109

6.1 About ADAMS/Car Analyses ............................................................................... 109

6.2 Types of Analyses ................................................................................................. 109

6.3 Introducing Suspension Analyses ......................................................................... 110

6.3.1 Suspension Analysis Process ......................................................................... 110

6.3.2 Suspension Assembly Roles .......................................................................... 111

6.3.3 Setting Suspension Parameters ...................................................................... 111

6.3.4 Submitting Suspension Analyses .................................................................. 111

6.4 Introducing Full-Vehicle Analyses ....................................................................... 114

6.4.1 Full-Vehicle Analysis Process ....................................................................... 114

6.4.2 About the Full-Vehicle Analyses .................................................................. 114

7 Creating and Simulating Suspensions ........................................................... 121

7.1 Starting ADAMS/Car Standard Interface ............................................................. 121

7.2 Creating Suspension Assemblies .......................................................................... 121

7.2.1 Creating a New Front Suspension Subsystem .............................................. 121

7.2.2 Creating a Suspension and Steering Assembly ............................................ 124

CONTENTS

IV

7.3 Performing a Baseline Parallel Wheel Travel Analysis ........................................ 125

7.3.1 Defining Vehicle Parameters ......................................................................... 125

7.3.2 Performing the Analysis ................................................................................ 126

7.3.3 Animating the Results .................................................................................... 127

7.4 Performing a Baseline Pull Analysis .................................................................... 127

7.4.1 Defining a Loadcase File ............................................................................... 127

7.4.2 Performing the Analysis ................................................................................ 129

7.4.3 Animating the Results .................................................................................... 130

7.5 Modifying the Suspension and Steering Subsystem ............................................. 130

7.5.1 Modifying Hardpoint Locations .................................................................... 130

7.5.2 Saving the Modified Subsystem .................................................................... 131

7.6 Performing an Analysis on the Modified Assembly ............................................. 131

8 Template Builder Tutorial ............................................................................. 133

8.1 Starting ADAMS/Car Template Builder ............................................................... 133

8.2 Creating Topology for Your Template ................................................................. 134

8.2.1 Creating a Template ....................................................................................... 134

8.2.2 Building Suspension Parts ............................................................................. 135

8.2.3 Creating the Wheel Carrier ............................................................................ 138

8.2.4 Creating the Strut............................................................................................ 139

8.2.5 Creating the Damper ...................................................................................... 140

8.2.6 Defining the Spring ........................................................................................ 140

8.2.7 Creating the Tie Rod ...................................................................................... 141

8.2.8 Creating the Toe and Camber Variables ....................................................... 142

8.2.9 Creating the Hub ............................................................................................ 142

8.2.10 Creating and Defining Attachments and Parameters ................................. 143

8.3 Creating a Suspension Subsystem......................................................................... 148

9 Creating and Simulating Full Vehicles .......................................................... 151

9.1 A Full-Vehicle Assembly ..................................................................................... 151

9.2 Performing a Single Lane-Change Analysis ......................................................... 153

9.3 Performing a Step Steer Analysis ......................................................................... 155

9.4 Performing a Quasi-Static Steady-State Cornering Analysis ................................ 156

9.5 Performing a Baseline ISO Lane-Change Analysis .............................................. 156

9.6 Modifying the Full-Vehicle Assembly ................................................................. 157


V

APPENDIX A: ADAMS/View keyboard shortcuts ......................................... 159

APPENDIX B: ADAMS/Car keyboard shortcuts ............................................ 162

REFERENCES ................................................................................................. 164


1

SectionⅠ- ADAMS/View

1 ADAMS/View Basics

ADAMS/View is a powerful modeling and simulating environment that lets you build,

simulate, and refine models of mechanical systems.

1.1 Introducing ADAMS/View

ADAMS/View lets you build models of mechanical systems and simulate the full-motion

behavior of the models. You can also use ADAMS/View to quickly analyze multiple design

variations until you find the optimal design. This chapter introduces you to ADAMS/View.

It includes the sections:

Steps in Modeling and Simulating

Build Your Model

Test and Validate Your Model

Refine Your Model and Iterate

Customize and Automate ADAMS/View

1.1.1 Steps in Modeling and Simulating

The steps that you use in ADAMS/View to create a model mirror the same steps that you

would use to build a physical prototype. These steps are shown in Figure 1.

Although we’ve listed the steps that you perform to create a model as though you create the

entire model at once and then test and refine it, we recommend that you build and test small

elements or subsystems of your model before you build the entire model. For example,

create a few modeling objects, connect them together, and then run a simple simulation to

test their motion and ensure that you are connecting them correctly. Once these are modeled

correctly, add more complexity to your model. By starting out slowly, you can ensure that

each subsystem works before moving on to the next step. We call this the crawl-walk-run

approach.

1.1.2 Build Your Model

You create your model in ADAMS/View by:

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Creating the Parts of Your Model

Adding Constraints and Motions to Mandate Part Movements

Adding Forces that Induce or Resist Part Movements

Figure 1.1 Steps in Modeling and Simulating

Each of these processes is explained below.

Creating the Parts of Your Model

You start building your model by building the physical attributes of the movable elements


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(parts) in your mechanical system. You can build the geometry using:

(1) ADAMS/View library of parts to create the simpler elements of your model.

(2) ADAMS/Exchange to import CAD geometry and realistically view the

behavior of your model.

Adding Constraints and Motions to Mandate Part Movements

Constraints define how parts are attached and how they are allowed to move relative to each

other. ADAMS/View provides a library of constraints including:

(1) Idealized joints that have a physical counterpart, such as a revolute (hinge) or

translational joint (sliding dovetail).

(2) Joint primitives that place a restriction on relative motion, such as the

restriction that one part always moves parallel to another part.

(3) Motions generators that drive your model through a prescribed distance,

velocity, or acceleration as a function of time.

(4) Associative constraints that define how pairs of constraints move, such a

couplers or gears.

(5) Two-dimensional curve constraints that define how a point or curve moves

along another curve.

Adding Forces that Induce or Resist Part Movements

You can also apply forces that act on your model. These forces will affect part motion and

reaction forces on constraints. ADAMS/View provides you with libraries of forces that

include:

(1) Flexible connectors, such as spring-dampers and bushings, those provide

pre-defined, compliant force relationships.

(2) Special forces, such as aerodynamic force, that provide pre-defined forces that

are commonly encountered.

(3) Applied forces that allow you to write your own equations to represent a wide

variety of force relationships. To help you write force equations, we’ve

provided a Function Builder, which steps you through writing a function and

evaluates the function before adding it to your model.

(4) Contacts that specify how bodies react when they come in contact with one

another when the model is in motion.

1.1.3 Test and Validate Your Model

After you create your model or at any point in the modeling process, you can run tests of

your model to ensure that it was created correctly and to verify its system characteristics.

You test your model by:

Defining Results to Be Output

Performing a Simulation

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Reviewing the Simulation Results

Validating Simulation Results

Defining Results to Be Output

When you run a simulation of your model, ADAMS/View automatically calculates

predefined information for the objects in your model, such as displacements and velocities.

You can also define measures or requests that ADAMS/View tracks during a simulation.

You can measure almost any characteristic of the objects in your model, such as the force

applied to a spring or the distance or angle between objects. As you run the simulation,

ADAMS/View displays strip charts of the measures that you requested so you can view the

results as the simulation occurs.

Performing a Simulation

After creating your model or at any point in the modeling process, you can run a simulation

of the model to verify its:

Performance characteristics

Response to a set of operating conditions

To perform a simulation, ADAMS/View submits the model to MDI’s analysis engine,

ADAMS/Solver, which formulates and solves the equations of motion for the model. As

ADAMS/Solver performs the analysis, ADAMS/View displays an animation of your model

in motion and displays strip charts tracking the measures that you specified.

ADAMS/View provides many different categories of simulations, including dynamic

simulations, which calculate the dynamic motion of your model, static equilibrium

simulations, and more. You can even use ADAMS/View to help you assemble your model.

Reviewing the Simulation Results

After a simulation is complete, you can rerun the animation of the simulation, pause it at

any frame in the animation, or change the camera angle. In addition, you can view the

results of the simulation by plotting them in ADAMS/PostProcessor.

ADAMS/PostProcessor lets you plot all of the measures that you specified, as well as plot

the result components that ADAMS/View automatically generates during a simulation.

ADAMS/PostProcessor lets you zoom in on your plot, plot any of the result components

against any other data, and view statistics about data in the plot, such as the slope of the

curve or the curve’s minimum and maximum values. A plot can contain multiple axes and

you can construct Bode and fast fourier transform (FFT) plots.

Validating Simulation Results

You can import numeric results from physical tests of a mechanical system and compare

them to the results of simulations in ADAMS/View to validate the accuracy of your model.

You can plot the test data over the ADAMS/View simulation results for quick and easy

comparison.


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1.1.4 Refine Your Model and Iterate

After you have run initial simulations to determine the basic motion of your model, you can

refine your model by adding more complexity to it, such as adding friction between bodies

and defining control systems using linear or general state equations. You can also enhance

its realism by changing rigid bodies to flexible bodies or joints to flexible connectors.

To help you compare alternative designs, you can build in parameters that change

automatically as you change your model. The parameters can be defined using:

Design points - Design points allow you to build automatic parameterization between

objects, as well as position and orient objects. They help you explore the effects of the

geometry and mechanical layout of your model. When you change the position of a design

point, the position of all objects defined relative to it automatically change.

Design variables - Design variables allow you to vary any aspect of a modeling object.

For example, you can define a variable for the width of a link or for the stiffness of a spring.

You can then run a design study that changes a single variable over a range of values to

investigate the sensitivity of the design to changes in this variable.

Optimize Your Model

ADAMS/View provides tools that help you find the optimal design for your mechanical

system:

(1) Design of experiments - Helps you to understand which design variables have

the greatest impact on a design objective.

(2) Optimization - Helps you find an optimal design. You define the design

objective and specify the parameters of the model that can change.

These tools automatically run several simulations, varying one or more modeling variables

with each new simulation.

1.1.5 Customize and Automate ADAMS/View

You can customize ADAMS/View so that it works and looks the way you want it to and

mimics your design environment. There are four major ways to customize it. You can:

(1) Customize the graphical interface - For example, you can create your own set

of menus or dialog boxes.

(2) Automate your work using macros - You can also speed up your work by

creating macros to perform complex or repetitive tasks. You can edit the

macros to include design variables to further customize and automate the

modeling process.

(3) Create your own ADAMS/View executable - The executable you create can

read in different ADAMS/View functions and execute commands.

(4) Edit ADAMS/View startup files - You can edit the files that ADAMS/View

1 ADAMS/View Basics

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reads when it first starts. These files can automatically load a model, execute

commands, or change menus or dialog boxes.

1.2 Working with the ADAMS/View

This chapter explains how to use the basic features of ADAMS/View.

1.2.1 Starting ADAMS/View

You or your system administrator can customize how you start ADAMS/View and how

ADAMS/View looks after you start it.

To start ADAMS/View in Windows:

On the Start menu, point to Programs, point to ADAMS 12.0, point to AView, and then select

ADAMS - View.

Starting a New Modeling Session

When you start ADAMS/View, ADAMS/View displays a Welcome dialog box that lets you

create a new modeling database or use an existing one. The Welcome dialog box also lets

you import modeling data and specify your working directory.

ADAMS/View also displays the Welcome dialog box when you use the New Database

command to create a new modeling database in which to store your models. The Welcome

dialog box is shown below.

1.2.2 ADAMS/View Main Window

After you start ADAMS/View, the ADAMS/View main window appears. Figure 1.2 shows

the default window. Your window may look different if it was customized.

The elements in the ADAMS/View main window are described below.

(1) Main toolbox - Displays commonly used tools for creating, editing, and

selecting modeling elements, as well as simulating the model and undoing

operations. The tools are shortcuts to using the menus in the menu bar.

(2) Window title bar - Displays the title of the ADAMS/View main window.

(3) Menu bar - Contains the headings of each menu. The menus contain all the

ADAMS/View commands for creating, simulating, and refining your model.

(4) Welcome dialog box - Steps you through starting your ADAMS/View session.

It appears when you first start ADAMS/View and when you create a new

modeling database.

(5) View triad - Displays the orientation of the global coordinate system.

(6) Status bar - Displays information messages and prompts while you work. Also


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contains tools for displaying information, commands, and stopping an

ADAMS/View operation.

Figure 1.2 Initial ADAMS/View Window

1.2.3 Starting a New Modeling Session

When you start ADAMS/View, ADAMS/View displays a Welcome dialog box that lets you

create a new modeling database or use an existing one. The Welcome dialog box also lets

you import modeling data and specify your working directory.

ADAMS/View also displays the Welcome dialog box when you use the New Database

command to create a new modeling database in which to store your models. The Welcome

dialog box is shown below.

1 ADAMS/View Basics

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Figure 1.3. Welcome Dialog Box

Select one of the options explained in Table 1.1 to indicate how you’d like to start using

ADAMS/View, and then select OK.

Table 1.1 Options in Welcome Dialog Box

The option: Does the following:

Create a new model Lets you start a new modeling session with a new

modeling database. Follow Steps 2 and 3 to create

the new modeling database.

Open an existing

database

Lets you open an existing modeling database. For more

information on opening existing databases.

Import a file Lets you start a new modeling session by reading in a

model from an ADAMS/View command file or an

ADAMS/Solver dataset.

Exit Lets you exit ADAMS/View without performing an

operation.

If you selected to create a new model, do the following:

(1) In the Model name text box, enter the name you want assigned to the new

model. You can enter up to 80 alphanumeric characters. You cannot include

special characters, such as spaces or periods.

(2) Select the gravity settings for the new model. You can select:

Earth Normal - Sets the gravity to 1 G downward.

No Gravity - Turns off the gravitational force.

Other - Lets you set the gravity as desired. The Gravity Settings dialog box

appears after you select OK on the Welcome dialog box.

(3) Select a preset unit system for your model. In all the preset unit systems, time is


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in seconds and angles are in degrees. You can set:

MMKS - Sets length to millimeter, mass to kilogram, and force to Newton.

MKS - Sets length to meter, mass to kilogram, and force to Newton.

CGS - Sets length to centimeter, mass to gram, and force to Dyne.

IPS - Sets length to inch, mass to slug, and force to PoundForce.

1.3 Defining the Modeling Environment

When you start a new session with ADAMS/View, it asks you to define your modeling

environment by specifying your unit system and gravitational force. Anytime you are

working with ADAMS/View you can redefine the modeling environment. The next sections

explain how to set up your modeling environment.

1.3.1 Specifying the Type of Coordinate System

When you first start ADAMS/View, it displays a view triad in the lower left corner. The

view triad displays the global coordinate system for the modeling database. By default,

ADAMS/View uses a Cartesian coordinate system as the global coordinate system with

three axes (x, y, and z). ADAMS/View attaches the ground part to the global coordinates

system and by default positions all other modeling objects to it.

You can change the default coordinate system from Cartesian to cylindrical or spherical.

ADAMS/View uses the default system for any values you enter and any values it displays.

ADAMS/View also uses the default system for values when importing and exporting data.

1. Types of Coordinate Systems

ADAMS/View lets you specify locations using three different types of coordinate

systems: Cartesian, cylindrical, and spherical. By default, ADAMS/View uses the Cartesian

coordinate system.

Cartesian Coordinates Cylindrical Coordinate System Spherical Coordinate System

Figure 1.4 ADAMS/View Coordinate System

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2. About Orientation Angles and Rotations

ADAMS/View uses three orientation angles to perform three rotations about the axes of a

coordinate system. These rotations can be space-fixed or body-fixed.

Space-fixed rotation: ADAMS/View applies the rotations about axes that remain in

their original orientation.

Body-fixed rotation: ADAMS/View applies the rotations about axes that move with

the body as it rotates. As ADAMS/View applies each rotation to an axis, it produces

a new set of axes.

You specify the order in which axes are rotated about as a sequence of three numbers

(1,2,3), which correspond to x-, y-, and z-axes, respectively. For example, a rotation order

of 313 produces rotations about the z-, then x-, and then y-axis. ADAMS/View provides

you with a set of 24 rotation sequences from which to choose. The most commonly used

rotation sequence, body 313, is the default sequence.

The right-hand rule defines the direction of positive rotation about each axis.

3. Setting the Default Coordinate System

1) Do one of the following:

On the Settings menu, select Coordinate System.

On the Move tool stack, select the Coordinate System tool .

The Coordinate Systems Setting dialog box appears.

2) Select the type of location coordinate systems.

3) Select the type of orientation coordinates and rotation sequence.

4) Select OK.

1.3.2 Setting Units of Measurement

You can set the units that ADAMS/View uses to define dimensions. ADAMS/View comes

with a predefined set of units. You can change the system of units you are using any time

during the modeling process.

To set the unit of measurement in ADAMS/View:

1) On the Settings menu, select Units. The Units Settings dialog box appears.


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2) Select the unit of measurement for each of the dimensions.

3) Select OK.

Units of Measurement in ADAMS/View

The units of measurement that ADAMS/View provides for you are shown in Table 1.2. It

also shows the default units used when you start a new session with a new modeling

database.

Table 1.2 Standard Units of Measurement

For the

dimension: Its supported units are: The default unit is:

Length Meter, Millimeter, Centimeter,

Kilometer, Inch, Foot, Mile

Millimeter

Mass Kilogram, Gram, PoundMass,

OunceMass, Slug, KilopoundMass

Kilogram

Force Newton, KilogramForce, Dyne, PoundForce,

OunceForce, KiloNewton, KilopoundForce,

MilliNewton

Newton

Time Second, Minute, Hour, Millisecond Second

Angle Radian, Degree Degree

Frequency Radians per second, Hertz Radians per second

1.3.3 Specifying Gravitational Force

You can specify the magnitude and direction of the acceleration of gravity. For each part

with mass, the gravitational force produces a point force at its center of mass.

To turn on and specify the gravitational force:

1) Do one of the following:

On the Settings menu, select Gravity.

On the Create Forces tool stack, select the Gravity tool .

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The Gravity Settings dialog box appears.

2) Select the Gravity check box to turn on gravity.

3) Set the acceleration of the gravity in the x, y, and z directions with respect to the

global coordinate system.

4) Select OK.

1.3.4 Specifying Working Directory

By default, ADAMS/View searches for and saves all files in the directory from which you

ran ADAMS/View. You can change the working directory.

To change the working directory for the current session:

1) On the File menu, select Select Directory.

2) Select the directory in which ADAMS/View should save files.

3) Select OK.


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2 Building Models in ADAMS/View

ADAMS/View provides a complete library of parts that you can create. ADAMS/View

provides you with three different types of parts.

Rigid Bodies: Parts in your models that have mass and inertia properties. They

cannot deform.

Flexible Bodies: Parts that have mass and inertia properties and can bend when

forces are applied to them. Basic ADAMS/View provides you with the ability to

create discrete flexible links. For more functionality, you can purchase

ADAMS/Flex.

Point Masses: Parts that have only mass. They have no extent and, therefore, no

inertia properties.

In addition, ADAMS/View provides a ground part that is already created for you. The

ground part is the only part in your model that must remain stationary at all times.

ADAMS/View creates the ground part automatically when you create a model. You can

also define a new or existing part as ground. The ground part does not have mass properties

or initial velocities and does not add degrees of freedom into your model.

2.1 Creating Parts

You can create rigid body geometry using the tools on the Geometric Modeling palette or

the Geometric Modeling tool stack on the Main toolbox. The palette and tool stack contain

the same tools so you can choose whichever one you are most comfortable using. The

Geometric Modeling palette and tool stack are shown in figure 2.1.

As you create geometry, ADAMS/View provides settings to assist you in defining the

geometry. It provides the settings in a container at the bottom of the palette or Main toolbox.

The settings change depending on the type of geometry that you are creating. For example,

Figure 2.1 shows the length, width, and depth values associated with creating link

geometry.

You can use the settings to control how you want ADAMS/View to define the geometry.

For example, when you create a link, ADAMS/View lets you specify its width, length, and

height before creating it. Then, as you create the link, these dimensions are set regardless of

how you move the mouse. You can also define design variables or expressions for these

setting values.

To display the Geometric Modeling palette:

From the Build menu, select Bodies/Geometry.


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To display the contents of the Geometric Modeling tool stack:

From the Main toolbox, right-click the Geometric Modeling tool stacks. By default,

the Link tool appears at the top of the tool stack.

Geometric Modeling palette Geometric Modeling tool

stack on Main toolbox

Figure 2.1 Geometric Modeling Palette and Tool Stack

2.1.1 Creating Construction Geometry

You can create several types of construction geometry. You draw construction geometry

normal to the screen or the working grid.

Types of construction geometry are shown in table 2.1.

The next sections explain how to create construction geometry.

Defining Points

Defining Coordinate System Markers

Creating Lines and Polylines

Creating Arcs and Circles

Creating Splines

Table 2.1 Types of construction geometry


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Type Tool An example Parameters Specified

Points

Attach Near/Don’t Attach

Location, Parent Part

Markers

Orientation, Location,

Parent Part

Polylines

One Line/Multiple Lines,

Open/Closed, Length, Vertex

Points Angle, Parent Part

Arcs

Radius, Start and End Angle,

Anchor CSM, Parent Part

Splines

Open/Closed, Knot Points,


1. Defining Points

Points define locations in three-dimensional space upon which you can build your model.

They allow you to build parameterization between objects, as well as position objects.

For example, you can attach a link to points so that each time you move the points, the

link’s geometry changes accordingly. You can also use points to define the location where

modeling objects connect, such as the point where a joint connects two parts. Points do not

define an orientation, only a location.

As you create a point, you define whether ADAMS/View should add it to ground or to

another part. In addition, you specify whether other parts near the same location should be

attached (parameterized) to the point. If you attach other bodies to the point, then the

location of those bodies is tied to the location of that point. As you change the location of

the point, the location of all attached bodies change accordingly.

To quickly access the Table Editor:

1) From the Geometric Modeling tool stack, select the Point tool .

2) From the settings container, select Point Table.

To create a point:

1) From the Geometric Modeling tool stack or palette, select the Point tool .

2) In the settings container, specify the following:

Whether you want the point added to ground or to another part in your model.

Whether you want to attach nearby objects to the point.

3) If you selected to add the point to another part in your model, select the part.


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4) Place the cursor where you want the point to be located and click the mouse button.

2. Defining Coordinate System Markers

You can create a marker defining a local coordinate system on any part in your model or

ground. The marker has a location (the origin of the coordinate system) and an orientation.

ADAMS/View automatically creates markers at the center of mass of all solid geometry and

at anchor points on geometry that define the location of the object in space. For example, a

link has three markers: two at its endpoints and one at its center of mass. ADAMS/View

also creates markers automatically for you when you constrain objects, such as add a joint

between parts.

ADAMS/View displays markers as triads. Figure 2.2 shows how markers appear for boxes

and links.

Figure 2.2 Marker Screen Icons

You create markers by specifying their location and orientation. You can align the

orientation of the marker with the global coordinate system, the current view coordinate

system, or a coordinate system that you define. When you define a coordinate system, you

specify one or two of its axes and ADAMS/View calculates the other axes accordingly.

ADAMS/View assigns the marker a default name. The default name is MARKER followed

by a number representing the marker (for example, MARKER_1, MARKER_2, and so on).

To create a marker:

1) From the Geometric Modeling tool stack or palette, select the Marker tool .


Whether you want the marker added to ground or to another part in your model.

How you want to orient the marker. From the Orientation option menu, select an

orientation method.

3) If you selected to add the marker to a part, select the part to which you want to add the

marker.

4) Place the cursor where you want the marker to be located and click.

5) If you selected to orient the marker to anything other than the global or view

coordinate system, select the directions along which you want to align the marker’s axes.

Do this for each axis that you selected to specify.

3. Creating Lines and Polylines

You can create both single- and multi-line segments (polylines). In addition, you can create


17

open or closed polylines (polygons).

To draw a single line:

1) From the Geometric Modeling tool stack or palette, select the Polyline tool .

2) In the settings container, do the following:

Specify whether you want to create a new part composed of the geometry or add

the geometry to an existing part or ground.

Set the type of line to be drawn to One Line.

If desired, set the length and angle of the line.

3) Position the cursor where you want the line to begin and click.

4) Move the cursor in the direction you want to draw the line.

5) When the line is the desired length and orientation, click again to end the line.

To draw an open or closed polyline:

1) From the Geometric Modeling tool stack or palette, select the Polyline tool .




Set the type of line to be drawn to Polyline.

If desired, set the length of the line segments.

Select whether you want a closed polyline (polygon) by selecting Closed.

3) Position the cursor where you want the polyline to begin and click.

4) To create the first line segment, drag the cursor and click to select its endpoint.

5) To add line segments to the polyline, continue dragging the cursor and clicking.

6) To stop drawing and create the open or closed polyline, right-click. If you selected to

create a closed polyline, ADAMS/View automatically draws a line segment between the

last and first points to close the polyline. Note that clicking the right mouse button does not

create another point.

4. Creating Arcs and Circles

You can create arcs and circles centered about a location. You begin drawing an arc by

specifying its starting and ending angles. You then indicate its center location and set its

radius and the orientation of its x axis. You can also specify the arc’s radius before you

draw it. ADAMS/View draws the angle starting from the x-axis that you specify and

moving counterclockwise (right-hand rule).

To draw an arc:

1) From the Geometric Modeling tool stack or palette, select the Arc tool .



18


the geometry to an existing part or ground. By default, ADAMS/View creates a

new part.

If desired, set the radius of the arc.

Specify the starting and ending angles of the arc. The default is to create a

90-degree arc from a starting angle of 0 degrees.

3) Click where you want the center of the arc and then drag the mouse to define the

radius of the arc and the orientation of the x-axis. ADAMS/View displays a line on the

screen to indicate the x-axis. If you specified the radius of the arc in the settings container,

ADAMS/View maintains that radius regardless of how you drag the mouse.

4) When the radius is the desired size, click.

To draw a circle:

1) From the Geometric Modeling tool stack or palette, select the Arc tool .


Specify whether you want to create a new part or add the geometry to an existing

part. By default, ADAMS/View creates a new part.

If desired, set the radius of the circle.

Select Circle.

3) Click where you want the center of the circle and then drag the mouse to define the

radius of the circle. If you specified the radius of the circle in the settings container,

ADAMS/View maintains that radius regardless of how you drag the mouse.

4) When the radius is the desired size, click.

5. Creating Splines

A spline is a smooth curve that a set of location coordinates define. You create splines by

defining the locations of the coordinates that define the curve or by selecting an existing

geometric curve and specifying the number of points to be used to define the spline.

To create a spline by selecting points on the screen:

1) From the Geometric Modeling tool stack or palette, select the Spline tool .




Select whether you want the spline to be closed or open.

3) Place the cursor where you want to begin drawing the spline and click.

4) Click the locations where you want the spline to pass through. You must specify at

least eight locations for a closed spline and four locations for an open spline.

5) To stop drawing the spline, right-click.

To create a spline by selecting an existing curve:

1) From the Geometric Modeling tool stack or palette, select the Spline tool .


19




Select whether you want the spline to be closed or open.

Select to create a spline by selecting a curve.

In the # Points text box, set how many points you want used to define the curve or

clear the selection of Spread Points and let ADAMS/View calculate the number of

points needed.

3) Select the curve.

2.1.2 Creating Solid Geometry

Solid geometries are three-dimensional objects. You can create solid geometry from

ADAMS/View library of solids or extrude closed wire geometry into a solid. In addition,

you can combine solid geometry into more complex geometry or modify the geometry by

adding features, such as fillets or chamfers.

Types of solid Geometry in ADAMS/View are shown in table 2.2.

Table2.2 ADAMS/View Solid Geometry

Type Tool An example Parameters

Box

Length (x), Height (y),

Depth(z),


Cylinders

Length (z), Radius,


Spheres/

Ellipsoids

3-Diameters,


Frustums

Length(z), Bottom and Top

Radii, Anchor CSM, Parent

Part


20

Torus

Radius of Ring (xy plane),

Radius of Circular

Cross-section ( to xy plane),


Link

Width, Depth,2

Anchor CSM (Length), Parent

Part

Plate

Thickness, Radius, Vertex

Locations, Anchor CSM,

Parent Part

Extrusion

Open/Closed Profile, Depth,


Revolution

Open/Closed Profile, Sweep

Angle, Anchor CSM, Parent

Part

Two-

Dimensional

Plane

Length (x), Height (y)

The following sections explain how to create solids from ADAMS/View library of solids.

1. Creating a Box

To create a box:

1) From the Geometric Modeling tool stack or palette, select the Box tool .




If desired, set any of length, height, or depth dimensions of the box.

3) Place the cursor where you want a corner of the box and click and hold down the left

mouse button.

4) Drag the mouse to define the size of the box. If you specified any of the length, height,

or depth dimensions of the box in the settings container, ADAMS/View maintains those

dimensions regardless of how you drag the mouse.


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5) Release the mouse button when the box is the desired size.

2. Creating Two-Dimensional Plane

To create a plane:

1) From the Geometric Modeling tool stack or palette, select the Plane tool .

2) In the settings container, specify whether you want to create a new part composed of

the geometry or add the geometry to an existing part or ground.

3) Place the cursor where you want a corner of the box and click and hold down the left

mouse button.

4) Drag the mouse to define the size of the box.

5) Release the mouse button when the box is the desired size.

3. Creating a Cylinder

To create a cylinder:

1) From the Geometric Modeling tool stack or palette, select the Cylinder tool .




new part.

If desired, set the length or radius dimensions of the cylinder in the settings

container.

3) Click where you want to begin drawing the cylinder.

4) Drag the mouse to size the cylinder. If you specified any of the length and radius

dimensions of the cylinder in the settings container, ADAMS/View maintains those

dimensions regardless of how you drag the mouse.

5) When the cylinder is the desired size, click.

4. Creating a Sphere

To create a sphere:

1) From the Geometric Modeling tool stack or palette, select the Sphere tool .




new part.

If desired, set the radius of the sphere.

3) Click where you want the center of the sphere.

4) Drag the mouse to size the sphere. If you specified a radius dimension for the sphere in

the settings container, ADAMS/View maintains that dimension regardless of how you drag

the mouse.

5) When the sphere is the desired size, click.

5. Creating a Frustum


22

To create a frustum:

1) From the Geometric Modeling tool stack or palette, select the Frustum tool .




If desired, set the length or radii of the frustum.

3) Click where you want to begin drawing the frustum.

4) Drag the mouse to size the frustum. If you specified the length or radii of the frustum

in the settings container, ADAMS/View maintains those dimensions regardless of how you

drag the mouse.

5) When the frustum is the desired size, click.

6. Creating a Torus

To create a torus:

1) From the Geometric Modeling tool stack or palette, select the Torus tool .




new part.

If desired, set the inner and outer radii of the torus.

3) Place the cursor where you want the center of the torus and click.

4) Drag the mouse to define the radius of the torus. If you specified the radii of the torus

in the settings container, ADAMS/View maintains those dimensions regardless of how you

drag the mouse.

5) When the torus is the desired size, click.

7. Creating a Link

To create a link:

1) From the Geometric Modeling tool stack or palette, select the Link tool .




If desired, set any of the length, width, or depth dimensions of the link.

3) Place the cursor where you want to begin drawing the link and click.

4) Drag the mouse until the link is the desired size and then release the mouse button. If

you specified the length, width, and depth of the link in the settings container,

ADAMS/View maintains those dimensions regardless of how you drag the mouse.

8. Creating a plate

To create a plate:

1) From the Geometric Modeling tool stack or palette, select the Plate tool .


23




If desired, set the thickness or radius of the corners of the plate.

3) Place the cursor where you want the first corner of the plate and click the mouse

button.

4) Click at each corner of the plate. You must specify at least three locations.

5) Continue selecting locations or right-click to close the plate.

9. Creating an Extrusion

To create an extrusion from existing curve geometry:

1) From the Geometric Modeling tool stack or palette, select the Extrusion tool .




If desired, set the length (depth) of the extrusion.

Specify the direction you want the profile to be extruded from the current working

grid.

3) Select the curve geometry.

To create an extrusion by selecting points:

1) From the Geometric Modeling tool stack or palette, select the Extrusion tool .




Specify whether or not you want to create a closed extrusion.

If desired, set the length of the extrusion.

Specify the direction you want the profile to be extruded from the current working

grid.

3) Place the cursor where you want to begin drawing the profile of the extrusion, and

click.

4) Click at each vertex in the profile; then right-click to finish drawing the profile.

2.1.3 Creating Complex Geometry

ADAMS/View provides you with many ways in which you can take simple geometry and

create complex geometry from it. You can create solid geometry that has mass from wire

geometry or create complex, open geometry that has no mass.

1. Chaining Wire Construction Geometry


24

You can link together wire construction geometry to create a complex profile, which you

can then extrude. The geometry to be chained together must touch at one endpoint and

cannot be closed geometry. ADAMS/View adds the final chained geometry to the part that

owns the first geometry that you selected.

To chain wire geometry together:

1) From the Geometric Modeling tool stack or palette, select the Chain tool .

2) Click each piece of the wire geometry to be chained. The Dynamic Model Navigator

highlights those objects in your model that can be chained as you move the cursor around

the main window.

3) After selecting the geometry to be chained, right-click to create the chained geometry.

2. Combining Geometry

Once you have created individual parts of solid geometry, you can combine them into one

part to create complex, solid geometry, referred to as constructive, solid geometry or CSG.

ADAMS/View creates the solid geometry using Boolean operations, such as union and

intersection.

(1) Creating One Part from the Union of Two Solids

ADAMS/View lets you create complex geometry by joining two intersecting solids.

ADAMS/View merges the second part you select into the first part resulting in a single part.

The union has a mass computed from the volume of the new solid. Any overlapping volume

is only counted once.

To create a part from the union of two solids:

1) From the Geometric Modeling tool stack or palette, select the Union tool .

2) Select the solid geometry to be combined. As you move the cursor, the Dynamic

Model Navigator highlights those objects that can be combined. The second part you select

is combined into the first part.

(2) Creating One Part from the Intersection of Two Solids

ADAMS/View lets you intersect the geometry belonging to two solids to create a single

part made up of only the intersecting geometries. ADAMS/View merges the second part

that you select with the geometry of the first part that you select and forms one rigid body

from the two geometries.

To create a part from the intersection of two overlapping solids:

1) From the Geometric Modeling tool stack or palette, select the Intersect tool .

2) Select the solid geometry to be combined. As you move the cursor, the Dynamic

Model Navigator highlights those objects that can be combined. The second part you select

is combined into the first part.

(3) Cutting a Solid from Another Solid

ADAMS/View lets you remove the volume where one solid intersects another solid to

create a new solid. ADAMS/View subtracts the geometry of the second part that you select


25

from the geometry of the first part. The remaining geometry belongs to the second part that

you selected.

To create a part from the difference of two solids:

1) From the Geometric Modeling tool stack or palette, select the Cut tool .

2) Select the solid geometry to be cut. As you move the cursor, the Dynamic Model

Navigator highlights those objects that can be cut. The second part you select is cut from the

first part.

(4) Splitting a Solid

After you’ve created a complex solid, often referred to as a CSG, using the Boolean

operations explained in the previous sections, you can split the complex solid back into its

primitive solids. ADAMS/View creates a part for each solid resulting from the split

operation.

To split a complex solid:

1) From the Geometric Modeling tool stack or palette, select the Split tool .

2) Select the solid geometry to be split. The Dynamic Model Navigator highlights those

objects in your model that can be split.

2.1.4 Adding Features to Geometry

You can add features to the solid geometry that you create, including chamfering the edges

of the geometry, adding holes and bosses, and hollowing out solids.

Chamfering and Filleting Objects

You can create different types of edges and corners on your solids. These include beveled

(chamfered) edges and corners and rounded (filleted) edges and corners. You can think of

creating filleted edges as rolling a ball over the edges or corners of the geometry to round

them.

When chamfering an edge or corner, you can set the width of the beveling. When filleting

an edge or corner, you can specify a start and an end radius for the fillet to create a variable

fillet.

Adding Holes and Bosses to Objects

You can create circular holes in solid objects and create circular protrusions or bosses on

the face of solid objects. Examples of a hole and boss on a link are shown below.

As you create a hole, you can specify its radius and depth. As you create a boss, you can

specify its radius and height.

Hollowing Out a Solid

You can hollow out one or more faces of a solid object to create a shell. As you hollow an

object, you can specify the thickness of the remaining shell and the faces to be hollowed.


26

2.1.5 Working with Point Masses

Point masses are points that have mass but no inertia properties or angular velocities. They

are computationally more efficient when rotational effects are not important.

To create or modify a point mass:

1) From the Build menu, point to Point Mass, and then select either New or Modify.

2) If you selected Modify, the Database Navigator appears. Select a point mass to

modify.

The Create or Modify Point Mass dialog box appears. Both dialog boxes contain the

same options.

3) If you are creating a point mass, enter a name for the point mass.

4) Set the mass of the point mass in the dialog box and adjust its location as desired. By

default, ADAMS/View places the point mass in the center of the main window with a mass

of 1 in current units.

5) Select the Comments tool on the dialog box and enter any comments you want

associated with the point mass.

6) Select OK.

2.2 Modifying Parts

Parts define the objects in your model that can have mass and inertia properties and can

move. All forces and constraints that you define in your model act on these parts during a

simulation. This chapter explains how to create and modify parts. It contains: modifying

rigid body geometry, modifying part properties, setting up materials.

2.2.1 Modifying Rigid Body Geometry

You can modify the geometry of a rigid body using: using hotpoints to graphically modify

geometry, using dialog boxes to precisely modify geometry, editing locations using the

location table.

Using Hotpoints to Graphically Modify Geometry

You can use hotpoints to resize and reshape the geometry of a rigid body. The hotpoints

appear at various locations on the geometry depending on the type of geometry.

Using Dialog Boxes to Precisely Modify Geometry

You can precisely control the size, location, and shape of rigid body geometry using modify

dialog boxes. In addition, you can change the name of the geometry as you modify it.

Editing Locations Using the Location Table

To specify the location of points in lines, polylines, splines, extrusions, and revolutions, you


27

can use the Location Table. The Location Table lets you view the points in the geometry

and edit them. You can also save the location information to a file or read in location

information from a file.

2.2.2 Modifying Part Properties

Each moving part in ADAMS/View can have the following properties in addition to having

geometry:

Location and name

Mass and inertia

Initial velocities

Initial location and orientation

ADAMS/View automatically calculates the total mass of the part and its inertia based on

the part’s volume and density. It also automatically calculates the initial velocity and

position for the part based on any other initial conditions and connections in your model.

2.3 About Constraining Your Model

After you’ve created the parts for your model, you need to define how they are attached to

one another and how they move relative to each other. You use constraints to specify part

attachments and movement. This section explains the different types of constraints and how

to add them to your model.

2.3.1 Types of Constraints

Constraints define how parts (rigid bodies, flexible bodies, and point masses) are attached to

one another and how they are allowed to move relative to each other. Constraints restrict

relative movement between parts and represent idealized connections.

ADAMS/View provides a library of constraints including:

Idealized joints - Have a physical counterpart, such as a revolute (hinge) or

translational (sliding dovetail) joint.

Joint primitives - Place a restriction on relative motion, such as the restriction that

one part must always move parallel to another part.

Motions generators - Drive your model.

Higher-pair constraints

2.3.2 Accessing the Constraint Creation Tools

You can create constraints using the tools on the Joint palette or the tools on the Joint and


28

Motion tool stacks on the Main toolbox. The palette contains the entire library of

constraints while the tool stacks contain only subsets of the most commonly used

constraints. The palette and tool stacks for creating constraints are shown in figure 2.3.

Figure 2.3 Constraint Palette and Tool Stacks

To display the Joint palette:

From the Build menu, select Joints.

To display the contents of the Joint or Motion tool stack:

From the Main toolbox, right-click the Joint or Motion tool stack.

By default, the Revolute tool appears at the top of the Joint tool stack and the

Rotational Motion tool appears at the top of the Motion tool stack.

2.3.3 Working with Joints

Idealized joints are mathematical representations of joints that have physical counterparts,

such as a revolute (hinge) or translational joint (sliding dovetail). ADAMS/View provides a


29

variety of idealized joints from which you can choose. The next sections explain the

different types of joints and how to create and modify them.

2.3.3.1 Working with Idealized Joints

Idealized joints connect two parts. The parts can be rigid bodies, flexible bodies, or point

masses. You can place idealized joints anywhere in your model. ADAMS/View supports

two types of idealized joints: simple and complex.

Simple joints directly connect bodies and include the following:

Table1 2.3 Simple joints in ADAMS/View

Icon Idealized Joints An example DOF

Translational Revolute

Revolute Joints

3 2

Translational Joints

2 3

Cylindrical Joints

2 2

Spherical Joints

3 0

Planar Joints

1 2

Constant-Velocity Joints

3 1


30

Screw Joints

3 2

Fixed Joints

3 3

Hooke Joint

3 1

Universal Joint

3 1

Complex joints indirectly connect parts by coupling simple joints. They include: Gear Joint

and Coupler Joint. See table 2.4.

Table1 2.4 Complex joints in ADAMS/View

Icon Idealized Joints An example

Gear Joint

Coupler Joint

To create a simple idealized joint:

1) From the Joint tool stack or palette, select the joint tool representing the idealized

joint that you want to create.


How you want the joint connected to parts. You can select the following:

1 location (Bodies Implicit) - Lets you select the location of the joint and have


31

ADAMS/View determine the two parts that should be connected. ADAMS/View

selects the parts closest to the joint location. If there is only one part near the joint,

ADAMS/View connects the joint to that part and ground.

2 Bodies - 1 Location - Lets you explicitly select the two parts to be connected by

the joint and the location of the joint. The joint remains fixed on the first part and

moves relative to the second part.

2 Bodies - 2 Locations - Lets you explicitly select the two parts to be connected by

the joint and the location of the joint on each part. You should use this option if you

are working in exploded view.

How you want the joint oriented. You can select:

Normal to Grid - Lets you orient the joint along the current working grid, if it is

displayed, or normal to the screen.

Pick Geometry Feature - Lets you orient the joint along a direction vector on a

feature in your model, such as the face of a part.

3) Select the first part to be connected using the left mouse button. If you selected to

explicitly select the parts to be connected, select the second part in your model using the left

mouse button.

4) Place the cursor where you want the joint to be located, and click the left mouse button.

If you selected to specify its location on each part, place the cursor on the second location,

and click the left mouse button.

5) If you selected to orient the joint along a direction vector on a feature, move the cursor

around in your model to display an arrow representing the direction along a feature where

you want the joint oriented. When the direction vector represents the correct orientation,

click the left mouse button.

To create a gear joint:

1) To create a gear, select the Gear tool on the Joint tool stack or palette. The

Constraint Create Complex Joint Gear dialog box appears.

2) In the Gear Name text box, enter or change the name for the gear. If you are creating

a gear, ADAMS/View assigns a default name to the gear.

3) In the Adams Id text box, assign a unique ID number to the gear. The ID is an integer

number used to identify the gear in the ADAMS/Solver dataset. You only need to specify

an ADAMS ID if you are exporting the model to an ADAMS/Solver dataset, and you want

to control the numbering scheme used in the file.

Enter a positive integer for the ID or enter 0 to let ADAMS set the ID for you.

4) In the Comments text box, add or change any comments about the gear to help you

manage and identify the gear. You can enter any alphanumeric characters. The comments

appear in the information window when you select to display information about the gear, in

the ADAMS/View log file, and in a command or dataset file when you export your model


32

to these types of files.

5) In the Joint Name text box, enter or change the two translational, revolute, or

cylindrical joints to be geared together. ADAMS/View automatically separates the joint

names with a comma (,).

6) In the Common Velocity Marker text box, enter or change the marker defining the

point of contact between the geared parts. You need to make sure the z-axis of the common

velocity marker points in the direction of motion of the gear teeth that are in contact.

To create a marker, right-click the Common Velocity Marker text box, and then select

Create.

7) Select OK.

To create a coupler joint:

1) From the Joint tool stack or palette, select the Coupler tool .

2) Select the driver joint to which the second joint is coupled.

3) Select the coupled joint that follows the driver joint.

2.3.3.2 Working with Joint Primitives A joint primitive places a restriction on relative motion, such as restricting one part to

always move parallel to another part. The joint primitives do not have physical counterparts

as the idealized joints do. You can, however, combine joint primitives to define a complex

constraint that cannot be modeled using the idealized joints.

Table 2.5 lists the different types of joint primitives that are available in ADAMS/View.

Table1 2.5 Joint Primitives in ADAMS/View

Icon The primitive An example Constrains the following DOF

T R

Inline

One part so that it can only

move along a straight line

defined on a second part. The

location of the inline joint on

the first part must remain on

the z-axis of the second part.

2 0

Inplane

One part so that it can only

move in a plane of a second

part. The origin of the inplane

joint on the first part must

remain in the xy plane of the

second part.

2 3


33

Orientation

The coordinate system of one

part so that it cannot rotate

with respect to a second part.

The axes of the coordinate

systems must maintain the

same orientation. The location

of the origins of the coordinate

systems does not matter.

2 2

Parallel axes

The z-axis of the coordinate

system of one part so that it

remains parallel to the z-axis

of the coordinate system of a

second part. The coordinate

system of the first part can

only rotate about one axis with

respect to the coordinate

system of the second part.

3 0

Perpendicular

axes

The coordinate system of one

part so that it remains

perpendicular to the z-axis of a

second part. The coordinate

system of the first part can

rotate about two axes with

respect to the second part.

1 2

To create a joint primitive:

1) From the Joint palette, select the joint primitive tool representing the joint that you

want to create.


How you want the joint connected to parts. You can select the following:

1 Location - Bodies implicit - Lets you select the location of the joint and have

ADAMS/View determine the two parts that should be connected. ADAMS/View

selects the parts closest to the joint location. If there is only one part near the joint,

ADAMS/View connects the joint to that part and ground.

2 Bodies - 1 Location - Lets you explicitly select the two parts to be connected by

the joint and the location of the joint.

2 Bodies - 2 Locations - Lets you explicitly select the two parts to be connected by

the joint and the location of the joint on each part. You should use this option if you

are working in exploded view.

How you want the joint oriented. You can select:

Normal to Grid - Lets you orient the joint along the current working grid, if it is

displayed, or normal to the screen.

Pick Geometry Feature - Lets you orient the joint along a direction vector on a

feature in your model, such as the face of a part.


34

3) If you selected to explicitly select the parts to be connected, select each part in your

model using the left mouse button.

4) Place the cursor where you want the joint to be located, and click the left mouse button.

If you selected to specify its location on each part, place the cursor on the second location

and click the left mouse button.



you want the joint oriented. When the direction vector represents the correct orientation,

click the left mouse button.

ADAMS/View creates the joint at the specified location.

2.3.3.3 Working with Higher-Pair Constraints ADAMS/View provides you with two types of higher-pair constraints: point curve and 2D

curve-curve. See table 2.6.

Table1 2.6 Higher-Pair Constraints in ADAMS/View

Icon Higher-Pair

Constraints An example Constrains the following

pin-in-slot

The point-curve constraint

restricts a fixed point defined

on one part to lie on a curve

defined on a second part.

The first part is free to roll

and slide on the curve that is

fixed to a second part. The

curve on the second part can

be planar or spatial, or open

or closed.

A point-curve constraint

removes two translational

DOF from your model.

Point-Follower

2D

curve-curve

A 2D curve-curve constraint

restricts a curve defined on

the first part to remain in

contact with a second curve

defined on a second part.

The curve-curve constraint is

useful for modeling cams

where the point of contact

between two parts changes

during the motion of the

mechanism. The curve-curve

constraint removes three

DOF from your model.

To create a point-curve constraint:


35

1) From the Joint palette, select the Point-Curve Constraint tool .

2) In the settings container, set whether or not you will be selecting an edge or curve:

Curves - Splines, chains, and data-element curves are all considered curves.

Edge - An edge is one of the wireframe outlines drawn on a solid.

3) Select a point on a part that will travel along a curve.

4) Select the curve or edge along which the point will travel. The curve can be closed or

open. Note that when you select a closed curve, the Dynamic Model Navigator highlights

only a portion of the curve. ADAMS/View will use the entire curve.

To create a 2D Curve-Curve constraint:

1) From the Joint palette, select the 2D Curve-Curve Constraint tool .

2) In the settings container, for each part, set whether or not you will be selecting an edge

or curve:

Curves - Splines, chains, and data-element curves are all considered curves.

Edge - An edge is one of the wireframe outlines drawn on a solid.

3) For a curve-on-curve cam, select a curve or edge that will travel along a second curve.

4) Select the curve along which the first curve will travel. The curve can be closed or

open. Note that when you select a closed curve, the Dynamic Model Navigator highlights

only a portion of the curve. ADAMS/View will use the entire curve.

2.3.3.4 Working with Motions generators

A motion generator dictates the movement of a part as a function of time. It supplies

whatever force is required to make the part satisfy the motion.

ADAMS/View provides you with the following types of motion:

Joint Motion - Prescribes translational or rotational motion on a translational,

revolute, or cylindrical joint. Each joint motion removes one DOF from your model.

Joint motions are very easy to create, but they limit you to motions that are applied

to the above listed joints and movements in only one direction or rotation.

Point Motion - Prescribes the movement between two parts. When you create a

point motion, you specify the direction along which the motion occurs. You can

impose a point motion on any type of idealized joint, such as a spherical or

cylindrical. Point motions enable you to build complex movements into your model

without having to add joints or invisible parts.

1. Joint Motion

You can create two types of joint motion.

Translational - For a translational motion, ADAMS/View moves the first part that

the joint connects along the z-axis of the second part.

Rotational - For a rotational motion, ADAMS/View rotates the first part that the

joint connects about the z-axis of a second part. The right-hand rule determines the

sign of the motion. The z-axis of the first part must be aligned with the z-axis of the


36

second part at all times. The angle is zero when the x-axis of the first part is also

aligned with the x-axis of the second part.

To create a joint motion:

1) From the Motion tool stack or the Joint palette, select the joint motion tool

representing the motion that you want to create. Select either:

to create a translational motion.

to create a rotational motion.

2) In the settings container, specify the speed of the motion in displacement units per

second. By default, ADAMS/View creates a rotational motion with a speed of 30 degrees

per second and a translational motion with a speed of 10 millimeters per second.

To enter a function expression or user-written subroutine, right-click the Speed text box,

point to Parameterize, and then select Expression Builder to display the ADAMS/View

Function Builder.

3) Use the left mouse button to select the joint on the screen to which the motion will be

applied.

Modifying a Joint Motion:

You can change several properties about a joint motion after you create it. The properties

include:

Joint to which the motion is applied.

Motion direction, either rotational or translational.

Motion definition, including displacement, velocity, or acceleration.

Initial conditions for displacement and velocity.

2. Point Motion

There are two types of point motion that you can create:

Single point motion - Prescribes the motion of two parts along or around one axis.

General point motion - Prescribes the motion of two parts along or around the three

axes (six DOF).

To create a point motion:

1) From the Motion tool stack or the Joint palette, select the tool representing the type of

point motion that you want to create. Select either:

to create a single point motion.

to create a general point motion.

2) In the settings container, specify the these options.

3) If you selected to explicitly select the parts to which the motion is to be applied, select

each part using the left mouse button.

4) Place the cursor where you want the motion to be located and click the left mouse

button. If you selected to specify its location on each part, place the cursor on the second

location, and click the left mouse button.


37


around in your model to display an arrow showing the direction you want the motion

oriented. When the direction vector shows the correct orientation, click the left mouse

button.

2.4 Applying Forces to Your Model

ADAMS/View provides the following types of forces: Applied forces, Flexible connectors,

Special forces, Contacts. This section introduces forces and explains how to create and

modify forces.

For every force that you define in ADAMS/View, you specify the following information:

Whether the force is translational or rotational.

To which part or parts the force is applied.

At what point or points is the force applied (only applies to translational forces).

Magnitude and direction of the force.

You can define force magnitudes in ADAMS/View in the following ways:

Enter values used to define stiffness and damping coefficients.

Enter a function expression using the ADAMS/View library of built-in functions.

Enter parameters that are passed to user-written subroutines that are linked to

ADAMS/View.

You can define force directions in ADAMS/View in one of two ways:

Along one or more of the axes of a marker.

Along the line-of-sight between two points.

2.4.1 Accessing the Force Tools

You can create forces using the tools on the Create Forces palette or the Create Forces tool

stack on the Main toolbox.

To display the Create Forces palette:

From the Build menu, select Forces.

To display the contents of the Create Forces tool stack:

From the Main toolbox, right-click the Create Forces tool stack. By default, the

Translational Spring-Damper tool appears at the top of the tool stack.


38

Figure 2.4 Create Forces Palette and Tool Stack

2.4.2 Constructing Applied Forces

Applied forces are forces that define loads and compliances on parts so they move in certain

ways. ADAMS/View provides a library of applied forces that you can use. Applied forces

give you a great deal of flexibility, but they require work to model simple forces. Instead of

using applied forces, you may want to consider using the flexible connectors, which model

several commonly used force elements, or special forces, which provide environmental and

complex forces.

ADAMS/View provides several types of applied forces that are defined as single-

component force and single-component torque, multi-component forces and multi-

component torque, General Force.

Applied forces in ADAMS/View are shown in table1 2.7.


39

Table1 2.7 Applied Forces in ADAMS/View

Icon Applied Forces Explain

Single-component Force

A single-component force applies a

translational force in one of two

ways: one movable part, two parts

Single-component Toque

A single-component torque applies a

rotational force to either one part or

two about a specified axis.

Multi-component forces

（Three-component force）

Multi-component forces apply

translational force between two parts

in your model using three orthogonal

components.

Multi-component toque

（Three-component torque）

Multi-component toques apply

rotational force between two parts in

your model using three orthogonal

components.

General Force

(6-Component Force/Torque)

General forces apply translational

and/or rotational force between two

parts in your model using six

orthogonal components.

To create a single-component force:

1) From the Create Forces tool stack or palette, select either:

to create a single-component force.

to create a single-component torque.


The number of parts and the nature of the force direction. You can select the

following:

Space Fixed - On One Body, Fixed

Body Moving -On One Body, Moving

Two Bodies - Between Two Bodies

How you want the force oriented. You can select:

Normal to Grid - Lets you orient the force normal to the current working grid, if it

is displayed, or normal to the screen.

Pick Feature - Lets you orient the force along a direction vector on a feature in your

model, such as along an edge or normal to the face of a part.

The characteristics of the force. You can select the following:


40

Constant force/torque - Enter a constant force or torque value or let

ADAMS/View use a default value.

Spring-Damper - Enter stiffness and damping coefficients and let ADAMS/View

create a function expression for damping and stiffness based on the coefficient

values. (Not available when you are using the Main toolbar to access the force

tool.)

Custom - ADAMS/View does not set any values for you, which, in effect, creates

a force with zero magnitude. After you create the force, you modify it by entering

a function expression or parameters to a user-written subroutine that is linked to

ADAMS/View.

3) Do one of the following depending on whether you are creating a single-component

force or torque:

For a single-component force, select the action body. If you selected to create a

torque between two parts, select the reaction body and then select the points of

application on the two bodies. Be sure to select the point of application on the action

body first.

For a single-component torque, select the action body. If you selected to create a

torque between two parts, select the reaction body and then select the points of

application on the two bodies. Be sure to select the point of application on the action

body first.

4) If you selected to orient the force along a direction vector on a feature, move the cursor


you want the force oriented. When the direction vector represents the desired orientation,

click.

To modify a single-component force:

1) Right-click the object whose properties you want to modify, point to the type of object,

and then select Modify. Display the Modify a Force or Modify a Torque dialog box.

The dialog box appears. The options available in the dialog box change depending on the


41

direction of the force. The following shows the Modify a Force dialog box when the force

was defined as applied to one part with the direction of the force moving with a direction

body.

2) Enter the values in the dialog box and select OK.

2.4.3 Constructing Flexible Connectors

ADAMS/View provides 5 types of flexible connectors: bushings, translational spring-

dampers, torsion spring, massless beam, field element.

2.4.2.1. Working with Bushings

A bushing is a linear force that represents the forces acting between two parts over a

distance. The bushing applies a force and a torque. You define the force and torque using

six components (Fx, Fy, Fz, Tx, Ty, Tz).

To create a bushing:

1) From the Create Forces tool stack or palette, select the Bushing tool .

2) In the settings container, specify the force applied and oriented to parts.

If desired, enter stiffness (K) and damping (C) coefficients in the Settings container.

3) Click the bodies.

4) Click one or two force-application points depending on the location method you

selected.

5) If you selected to orient the force along a direction vector using a feature, move the

cursor around in your model to display an arrow that shows the direction along a feature

where you want the force oriented. Click when the direction vector shows the correct z-axis

orientation.

2.4.2.2 Working with Translational Spring-Dampers

A translational spring-damper represents forces acting between two parts over a distance

and along a particular direction. You specify the locations of the spring-damper and points

on two parts. ADAMS/View calculates the spring and damping forces based on the distance

between the locations on the two parts and their rate of change, respectively.

To create a spring-damper:

1) From the Create Forces palette or tool stack, select the Translational Spring-

Damper tool .

2) If desired, enter stiffness (K) and damping (C) coefficients in the Settings container.

3) Select a location for the spring-damper on the first part. This is the action body.

4) Select a location for the spring-damper on the second part. This is the reaction body.

2.4.2.3 Adding a Torsion Spring

A torsion spring force is a rotational spring-damper applied between two parts.


42

From the Create Forces palette or tool stack, select the Torsion Spring tool to create

a torsion spring.

2.4.2.4 Adding a Massless Beam

You can create a massless beam with a uniform cross-section. You enter values of the

beam’s physical properties, and ADAMS/Solver, calculates the beam transmits forces and

torques between the two parts.

To create a beam:

1) From the Create Forces palette or tool stack, select the Massless Beam tool .

2) Select a location for the beam on the first part. This is the action body.

3) Select a location for the beam on the second part. This is the reaction body.

4) Select the direction in the upward (y) direction for the cross-section geometry.

2.4.2.5 Adding a Field Element

The field element can apply either linear or nonlinear force.

To specify a linear field, enter values that define a six-by-six stiffness matrix, translational

and rotational preload values, and a six-by-six damping matrix. The stiffness and damping

matrixes must be positive semidefinite, but need not be symmetric.

To specify a nonlinear field, use the user-written subroutine to define the three force

components and three torque components.

From the Create Forces palette or tool stack, select the Field Element tool to create a

field.


43

3 Simulating Models in ADAMS/View

After you’ve built your model, you can perform a variety of simulations on the model to

investigate how it will perform under various operating conditions.

During a simulation, ADAMS/View performs the following operations:

Sets the initial conditions for all the objects in your model.

Formulates appropriate equations of motion based on the laws of Newtonian

mechanics that predict how objects in your model will move given the set of forces

and constraints acting on them.

Solves the equations to within your specified accuracy tolerance for such

information as part displacements, velocities, and acceleration, as well as applied

and constraint forces.

Temporarily saves the data calculated so that you can investigate your results using

animations, plots, and numerical signal processing. You can also permanently save

your results in your modeling database.

3.1 Types of Simulations

You can run five types of simulations in ADAMS/View using ADAMS/Solver,

ADAMS/View’s analysis engine:

Dynamic - A dynamic simulation provides a time-history solution for displacements,

velocities, accelerations, and internal reaction forces in your model driven by a set of

external forces and excitations. A dynamic simulation is also known as a kinetic simulation.

During a dynamic simulation, ADAMS/Solver solves the full set of nonlinear differential

and algebraic equations (DAEs). It is a computationally demanding simulation and is meant

to be used with models that have one or more degrees of freedom (DOF).

Kinematic - A kinematic simulation enables you to determine the range of values for the

displacement, velocity, and acceleration of any point of interest in the model independent of

forces applied to it. During a kinematic simulation, ADAMS/Solver solves only the reduced

set of algebraic equations. This type of simulation, therefore, is only available for models

with zero DOF.

If you specify the mass and inertia properties of bodies in your model, a kinematic

simulation also calculates the corresponding applied and reaction forces required to

generate the prescribed motions.

Static - A static simulation attempts to find a configuration for the parts in your model for

which all the forces balance. This configuration is often referred to as an equilibrium


44

configuration. Velocities and accelerations are set to zero for static simulations, so inertial

forces are not taken into consideration. A static simulation is for use with models that have

one or more DOF so ADAMS/Solver can move parts around as it seeks to balance all the

forces acting on the model.

Assemble - An assemble simulation attempts to correct any broken joints that

ADAMS/Solver sees as being defined incorrectly. It also attempts to resolve any conflicts

in the initial conditions you specified for the entities in your model. An assemble simulation

is also known as an initial conditions simulation.

Linear - A linear simulation lets you linearize your nonlinear dynamic equations of motion

about a particular operating point in order to determine natural frequencies and

corresponding mode shapes. You must purchase ADAMS/Linear to perform a linear

simulation.

3.2 Accessing the Simulation Controls

You access simulation controls using the Simulation tool and the corresponding Simulation

container on the Main toolbox or using the tools on the Simulation Control dialog box. The

dialog box contains a complete set of simulation controls, while the Simulation container

contains only a subset of the most commonly used simulation controls. The Simulation

container on the Main toolbox and the Simulation Controls dialog box are shown in figure

3.1.

Figure 3.1 Simulation Controls

To display the Simulation container on the Main toolbox:


45

On the Main toolbox, select the Simulation tool .

To display the Simulation Control dialog box, select one of the following:

On the Simulation container on the Main toolbox, select More.

On the Simulate menu, select Interactive Controls.

3.3 Performing an Interactive Simulation

You use interactive simulation controls to quickly run a single simulation and experiment

with different simulation parameters and options. Simulating interactively is helpful when

you are not sure exactly what your model will do or which options you need.

When you perform an interactive simulation, ADAMS/View submits one or two simple

commands to ADAMS/Solver based on the type of simulation, how long the simulation will

last, and the frequency with which you want data to be output.

To perform an interactive simulation, you need to tell ADAMS/View the following

information:

Type of simulation to be performed.

Time interval over which ADAMS/View should perform the simulation.

How often ADAMS/View should output data and temporarily store it in the

modeling database for use with animations and plots. For each output time step,

ADAMS/View creates a frame for animation and a data point for plotting and signal

processing.

To run an interactive simulation:

1) On the Main toolbox, select the Simulation tool .

2) From the Simulation Type option menu, select the type of simulation you want

ADAMS/View to perform:

Default - If your model contains zero degrees of freedom (DOF), ADAMS/View

performs a kinematic simulation. If your model has one or more DOF,

ADAMS/View performs a dynamic simulation.

Dynamic - Request a dynamic simulation.

Kinematic - Request a kinematic simulation.

Static - Request a static simulation.

3) Enter the time interval over which the simulation takes place and set how you want it

defined. You can select:

End Time - Specify the absolute point in time at which you want the simulation to

stop.

Duration - Specify the amount of time over which you want the simulation to run.


46

Forever - ADAMS/View continues simulating until you stop the simulation or

until it can no longer solve the equations of motion to within your specified

tolerance. This option is only available on the Simulation Control dialog box.

4) Set the frequency with which ADAMS/View outputs data during your simulation. You

can specify:

Step Size, which represents the amount of time, in current model units, between

output steps. The output frequency remains constant even if you change your

simulation end time or duration. For example, enter a step size of 0.01 seconds to

specify an output period of 0.01 seconds per step, which yields an output frequency

of 100 steps/second.

Steps, which represents the total number of times you want ADAMS/View to

provide output information over your entire simulation. For example, specify 50

steps over a 1-second simulation interval to define an output period of 0.02 seconds

per step, which yields an output frequency of 50 steps/second.

5) Select the Simulation Start tool .

To stop a simulation:

Select the Simulation Stop tool .

ADAMS/Solver stops any further processing, and the modeling objects appear in the

positions that ADAMS/Solver last successfully calculated.

3.4 Viewing and Controlling Animations

After you’ve simulated your model, you can animate the results. Animations replay the

frames that ADAMS/Solver calculated during a simulation. Animations help you review

and study the part movements within your model.

3.4.1 About Animating Your Simulation Results

Animations provide instant feedback to you as your simulation runs. When you perform a

simulation, ADAMS/Solver, the analysis engine, creates one animation frame for every

output step that you request in the simulation. For example, if you performed a simulation

from 0.0 to 10.0 seconds and asked for output every 0.1 seconds, ADAMS/Solver records

data at 101 steps or frames. It creates a frame every tenth of a second for ten seconds plus

one at time 0.0.

By default, each time you run a simulation, ADAMS/Solver replaces the previous

animation frames. To replay earlier animations, you must save them in your modeling

database.

During animations, ADAMS/View displays frames as quickly as it can based on the


47

graphics capability of your computer hardware.

3.4.2 Accessing the Animation Controls

You can work with animations using the Animation container on the Main toolbox or using

the tools on the Animation Control dialog box. The dialog box contains the complete set of

animation controls, while the Animation container contains only the most commonly used

animation controls. The Animation container on the Main toolbox and the Animation

Controls dialog box are shown in figure 3.2.

Figure 3.2 Animation Container and Animation Control Dialog Box

To display the Animation container on the Main toolbox:

On the Main toolbox, select on the Animation tool .

To display the Animation Control dialog box, do one of the following:

On the Animation container on the Main toolbox, select More.

From the Review menu, select Animation Controls.

3.4.3 Playing Animations

You can replay an animation again after the simulation ends to investigate the results of a

simulation, as long as the results of the simulation have been stored in your modeling

database. By default, ADAMS/View only stores the last simulation you performed. You can

either manually store a particular simulation, or you can set ADAMS/View so that it


48

automatically stores all your simulations.

You can play animation frames forwards or backwards, speed them up or slow them down,

pause and continue an animation, rewind to an earlier frame, continuously play an

animation in a loop, or play only a certain portion of the entire sequence of frames.

Playing an Animation

When you play an animation, ADAMS/View plays every frame by default. You can rewind

an animation and play the animation at various speeds as explained in table 3.1. During

fast-forward and fast-backward play modes, ADAMS/View plays only every fifth frame.

Table 3.1 Animation Play Options

To play an animation: Select the tool:

Forwards Play-forward tool

Backward Play-backward tool

Fast-forward mode Play-fast-forward tool

Fast-backward mode Play-fast-backward tool

Stopping an Animation

You can pause an animation at any time instead of waiting for it to complete.

To stop an animation, do one of the following:

On the Main toolbox or the Animation Control dialog box, select the Pause tool

.

On the status bar, select the Stop tool .

Press the Esc key.


49

4 Examples

This chapter provides overview information and step-by-step procedures for building,

simulating, and refining a model using ADAMS/View.

4.1 The Latch Design Problem

In this tutorial, you’ll build a latch model that is required to securely clamp two halves of

large shipping containers together.

4.1.1 Introducing the Latch Design Problem

Figure 4.1 shows an illustration of the physical model of the latch.

Figure 4.1 Physical Model of Hand Latch Design

The latch model must meet the following design requirements:

Exerts at least 800 N clamping force.

Is hand-actuated by less than 80 N force.

Is hand released with minimal effort.

Must work within a given envelope.

Clamping remains secure under vibration.

Figure 4.2 shows a virtual model of the latch. The latch is clamped by pushing down on the

4 Examples

50

operating handle at POINT_4. This causes the pivot to rotate around POINT_1 in a

clockwise direction, drawing back POINT_2 of the hook. As this happens, POINT_8 of the

slider is forced downward. Finally, as POINT_8 passes through the line between POINT_9

and POINT_3, the clamping force reaches its maximum. POINT_8 should move below the

line created by POINT_3 and POINT_9, followed by the operating handle coming to rest on

the top of the hook. This sets the latch near the maximum force point, but allows a

reasonable release force to open the latch.

Figure 4.2 ADAMS/View Latch Model

Based on the description of the latch operation, the relative layout of POINT_1 through

POINT_9 is important in ensuring that the latch will meet the design requirements.

Therefore, when your latch model is assembled and tested, you will want to change the

relative locations of the points to see their effect on the design requirements.

4.1.2 Building Model

In this section, you start ADAMS/View and create a modeling database containing a new

model named Latch. A modeling database contains all your work in the current session of

ADAMS/View. It contains any models you create, their attributes, simulation results, plots,

customized menus and dialog boxes, and any preferences you set.

ADAMS/View assigns to the parts you create the material type of steel, with a material

density of 7801.0 kg/m3.


51

You build the latch model in two basic sections:

Building the Pivot and Handle

Building the Hook and Slider

Figure 4.3 shows the latch as it should look when you have finished it.

Figure 4.3 Latch in Build Phase

1. To start ADAMS/View and Setting Up Your Work Environment

(1) To start ADAMS/View in the Windows environment

1) Select Start. start ADAMS/View, Select Create a new model from the Welcome

dialog box.

2) Replace the contents of the Model name text box with Latch.

3) Select OK.

(2) Setting Up Your Work Environment

1) Setting up units: From the Settings menu, select Units. Set the units of length to

centimeter. Select OK.

2) Setting up Working Grid: From the Settings menu, select Working Grid. Set the

grid size along X and Y to 25, and the grid spacing at 1. Select OK.

4 Examples

52

3) Setting up Icons: From the Settings menu, select Icons. In the New Size text box,

enter 1.5. Select OK.

4) To display the Coordinates window: From the View menu, select Coordinate

Window. The Coordinates window appears

2. Creating Design Points

1) Right-click the Rigid Body tool stack (Link tool is on top by default) to display the

tool stack containing the Point tool.

2) Select the Point tool and click the locations shown in Table 4.1 to place design

points. Use the default settings for point, which are Add to Ground and Don’t Attach.

Table 4.1 Points Coordinate Locations

X location: Y location: Z location:

POINT_1 0 0 0

POINT_2 3 3 0

POINT_3 2 8 0

POINT_4 -10 22 0

3. Creating the Pivot


53

1) Select the Plate tool .

2) In the Thickness text box, enter 1, and then press Enter.

3) In the Radius text box, enter 1, and then press Enter.

4) Click the location of POINT_1, POINT_2, and POINT_3.

5) To close the plate geometry, right-click.

6) Right-click the plate part. A pop-up menu appears.

7) Point to Part: PART_2, and then select Rename.

8) Replace PART_2 with pivot, Select OK.

4. Creating the Handle

1) Select the Link tool .

2) Click POINT_3, then POINT_4 to create a link between the two points.

3) Rename the link part, Part: PART_3, to handle, to represent the handle part as shown

in Figure 4.

5. Creating the Hook

1) Select the Extrusion tool .

2) Be sure that Create profile by: is set to Points and Closed is selected.

3) Select Path: to About Center.

4) In the Length text box, enter 1, and then press Enter.

5) Click the locations listed in Table 4.2.

Table 4.2 Extrusion Coordinate Values


5 3 0

3 5 0

-6 6 0

-14 6 0

-15 5 0

-15

-14

3

1

0

0

-12 1 0

-12 3 0

-5 3 0

4 2 0

4 Examples

54

6) To close the extrusion, right-click.

Note: Sometimes ADAMS/View snaps to the nearest object instead of snapping to a

coordinate value. To override this, hold down the Ctrl key and move the cursor until you

select the desired coordinate.

7) Change the name of the extrusion part to hook.

6. Creating the Slider

1) Create two more design points, POINT_8 and POINT_9, at the locations shown in

table 4.3.



POINT_8 -1 10 0

POINT_9 -6 5 0

2) Create a link connecting these two new design points. Again, before you click, make

sure the point labels are visible.

3) Rename the link part to slider.

7. Connecting the Parts Using Revolute Joints

1) Select the Revolute Joint tool .

2) To select the parts to attach, click the pivot and ground (the background).

3) Click POINT_1 to set the joint’s location. The revolute joint at POINT_1 should look

like this:

4) Select the Revolute Joint tool again.

5) Select the pivot, the handle, and POINT_3.

6) Place revolute joints at the following locations using the construction method 2 Bod -

1 Loc, and Normal To Grid:

Between the handle and the slider at POINT_8.


55

Between the slider and the hook at POINT_9.

Between the hook and the pivot at POINT_2.

8. Simulating the Motion of Your Model

1) Select the Simulation tool .

2) Set up a simulation with an end time of 1 second and 50 steps.


4) To return to the initial model configuration, select the Reset tool .

9. Saving Your Database

Use the Save Database As command to save the current modeling database as an

ADAMS/View binary file. Saving your modeling database as a binary file saves all

modeling information.

From the File menu, select Save Database As, and then save the file as build.

4.1.3 Testing Your First Prototype

In this section, you prepare the latch model for virtual testing, and then proceed to test it.

Virtual tests allow you to quickly set up and tear down tests in the virtual environment.

1. Creating the Ground Block

You use the Box tool to create a ground block. The ground block represents the surface on

which the hook slides.

1) Select the Box tool , and change its construction method from New Part to On

Ground.

2) Click at location (-2, 1, 0) and drag to (-18, -1, 0). Alternatively, you can click at the

start location and then click again at the end location.

3) Rename the part ground to ground_block.

2. Adding a Three-Dimensional Contact

1) Use the Dynamic Pick tool to zoom in on the area around the hook end.

2) From the Force (Connector) toolstack, select the Contact tool . The Create

Contact dialog box appears.

3) Right-click the First Solid text box, point to Contact_Solid, and then select Pick.

Select the hook (EXTRUSION_7).

4) Now do the same for the Second Solid text box, selecting the ground_block

(BOX_11).

5) Because you will use the default values for the contact force, select OK.

6) Select the Select tool, and then select the Fit tool .

3. Adding a Spring

1) Select the Translational Spring-Damper tool to create a spring between the ground

4 Examples

56

and the hook.

2) In the Spring container of the Main Toolbox, select the toggle for spring stiffness

coefficient, K, and for damping coefficient, C.

3) Set K to 800 and C to 0.5.

4) To add the spring, click at the following locations:

(-14, 1, 0) (make sure the hook vertex, .HOOK.EXTRUSION_7.V16, is selected,

not the coordinate location).

(-23, 1, 0)

A red spring appears.

4. Creating a Handle Force

In this section you create a handle force with a magnitude of 80N, representing a reasonable

force to be applied by hand.

1) Select the Force (Single-Component) tool and do the following in the Force

container on the Main Toolbox:

Set the Run-time Direction to Space Fixed.

Set the Characteristic to Constant.


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Select Force, and then set it to 80.

2) Select the following in the order listed:

The handle

A marker near the handle end point

The location -18, 14, 0

5. Creating a Measure on the Spring Force

1) Right-click the spring, point to Spring: SPRING_1, and then select Measure. The

Assembly Measure dialog box appears.

2) Set Characteristic to force.

3) Select OK. The spring measure strip chart appears.

4) Run a 0.2 second, 50-step simulation.

A graph of the clamping force appears during the simulation, as shown next:

5) Select the Reset tool to return to the initial model configuration.

6. Creating an Angle Measure

1) From the Build menu, point to Measure, point to Angle, and then select New. The

Angle Measure dialog box appears.

2) In the Measure Name text box, enter the measure name as overcenter_angle.

3) Right-click the First Marker text box, point to Marker, and then select Pick.

4) Pick the markers to enter in your measure as shown in row 1 of Table 4.4 and

illustrated in Figure 4.4.

Table 4.4 Overcenter_angle Measure Markers

Angle points: Marker location: Coordinate values:

First Point Any marker at POINT_8 -1, 10, 0

Middle Point Any marker at POINT_3

(angle vertex)

2, 8, 0

Last Point Any marker at POINT_9 -6, 5, 0

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Figure 4.4 Graphical Representation of overcenter_angle

5) Repeat the above two steps for the Middle Marker and Last Marker.

6) Select OK to display your angle measure strip chart as shown next:

7. Creating a Sensor

You now create a sensor to detect when overcenter_angle goes below zero, meaning that the

latch has toggled properly. When this condition is met, the sensor automatically stops the

simulation.

1) From the Simulate menu, point to Sensor, and then select New.

The Create Sensor dialog box appears.

2) Modify the Create Sensor dialog box as shown next, and then select OK:


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8. Saving Your Model

Save your latch model to record your progress.

From the File menu, select Save Database As, and then save this file as test.

9. Simulating Your Model

1) Select the Simulation tool and run a 0.2-second simulation with 100 steps.

As the simulation proceeds, ADAMS/View updates the strip charts for the spring force and

angle measures to show that the sensor stopped the simulation.

A message window also appears alerting you that ADAMS/View stopped the simulation

because of the sensor.

These strip charts show that ADAMS/View stopped the simulation as the latch reached the

toggle point:

2) Select the Reset tool to return to the initial model configuration.

4.1.4 Validating Results Against Physical Test Data

In this section, you compare physical test data with virtual test data. By comparing the two

sets of data, you immediately know the limitations of your model compared to the physical

prototype, and you will have all the data in one place to be able to eliminate the differences.

1. Importing Physical Test Data

1) From the File menu, select Import. The File Import dialog box appears.

2) Set the File Type to Test Data.

3) Make sure that the Create Measures option is selected.

4) In the File to Read text box, enter: install_dir/aview/examples/Latch/test_dat.csv,

where install_dir is the directory where ADAMS is installed.

5) In the text box to the right of the Model Name menu, enter .Latch.

6) Select OK.

2. Creating a Plot Using Physical Test Data

1) On the Review menu, select Postprocessing or press F8.

ADAMS/View launches ADAMS/PostProcessor (see Figure 4.5), a post-processing

tool that lets you view the results of simulations you performed.

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Figure 4.5 ADAMS/PostProcessor

2) At the bottom left of the dashboard, set Source to Measures.

3) From the Simulation list, select test_dat.

4) At the bottom right of the dashboard, set Independent Axis to Data.

A browser, named Independent Axis Browser, appears. It lets you select data for the

horizontal axis.

5) Select MEA_1.

6) Select OK.

7) From the dashboard, from the Measure list, select MEA_2, for the vertical axis data.

8) Select Add Curves to add the new data to the plot.

ADAMS displays the plot of the two measures as shown next:

3. Modifying Your Plot Layout

1) From the treeview, double-click page_1. Select plot_1. In the Title text box, enter


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Latch Force vs. Handle Angle. Press Enter.

2) From the treeview, double-click plot_1, select haxis. In the Label text box, enter

Degrees, and then press Enter.

3) Repeat the procedure for vaxis, labeling it Newtons.

4) From the treeview, select curve_1. In the Legend text box, enter Physical Test Data.

Your plot should look similar to the one shown next:

4. Creating a Plot Using Virtual Test Data

1) In the dashboard, from the Simulation list, select Last_Run (...).

2) Set Independent Axis to Data. The Independent Axis Browser appears.

3) Select overcenter_angle, for the horizontal axis data. Select OK.

4) From the Measure list, select SPRING_1_MEA_1, for the vertical axis data.

5) Select Add Curves.

6) Change the legend text for this curve to Virtual Test Data.

7) From the File menu, select Close Plot Window.

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5. Saving Your Model

From the File menu, select Save Database As, and then save the file as validate.

4.1.5 Refining Your Design

In this chapter you refine your model to add more parametrics to the critical point locations.

This allows you to compare different layouts of the model to the clamping force.

1. Creating Design Variables

1) Right-click the design point POINT_1 (0, 0, 0), point to Point: POINT_1, and then

select Modify. The Table Editor appears.

2) Select the Loc_X cell for POINT_1.

3) Right-click the input box at the top of the Table Editor, point to Parameterize, point

to Create Design Variable, and then select Real.

This creates a design variable named .Latch.DV_1 with the value of 0.

4) Select the Loc_Y cell for POINT_1.

5) Repeat Step 3.

6) Repeat the above procedure for the x and y locations of POINT_2, POINT_3,

POINT_8, and POINT_9.

7) Select Apply.

2. Reviewing Design Variable Values

After you’ve created all the design variables, you can display their range and allowed values.

ADAMS/View sets the design variable range based on the envelope requirements for the

latch. It automatically assigns a ±10% relative range to the design variables, except when

the design variable real value is 0. When the design variable value is 0, the range is set as

±1 absolute.

If you want to open up the range to different values, you must modify the range values and

possibly the delta type

1) At the bottom of the Table Editor, select the Variables option.

2) Select Filters. The Variables Table Editor Filters dialog box appears.


63

3) Select Delta Type.

4) Be sure that Range is selected.

5) Select OK.

The Table Editor changes to show you the range of the design variables.

6) Select OK.

7) Save your model as refine.

4.1.6 Iterating Your Design

In this section, you work on arriving at an improved design that meets the specifications and

includes all necessary behavior of the physical latch. You set up some design studies for a

few points to find a case that maximizes peak clamping force, while making sure the handle

toggles overcenter.

1. Performing a Manual Study

1) From the Build menu, point to Measure, and then select Display.

2) Select SPRING_1_MEA_1.

3) Select OK.

4) Run a .2 second, 100-step simulation and then return to the initial model configuration.

ADAMS/View updates the spring measure strip chart.

5) Right-click the spring force curve in the strip chart. Point to Curve: Current, and then

select Save Curve.

6) From the Build menu, point to Design Variable, and select Modify.

7) Double-click on DV_1.

8) Change the standard value of DV_1 to 1.0.

9) Select OK.

10) Run a .2 second, 100-step simulation.

This new plot shows a comparison of the spring force measure for the two cases. The new

curve shows better draw on the spring.

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11) Change DV_1 back to 0.0, its original value.

2. Running a Design Study

Run a design study to quickly look at a range of design variable values, and see how they

affect the design. ADAMS/View gives you the option of displaying various plots, as well as

a design study report.

1) From the Simulate menu, select Design Evaluation.

2) Fill out the dialog box that appears so it matches the one shown here. Leave the dialog

box open.

3) In the Design Evaluation Tools dialog box, select Display.

4) To see all the options, select More.

5) Set Time Delay to 0.0.


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6) Set Chart Objective, Chart Variables, and Show Report to Yes.

7) In the Solver Settings dialog box, select Close.

8) In the Design Evaluation Tools dialog box, select Start.

ADAMS displays the following plots and a design study report:

Spring Force Plot SPRING_1_force versus DV_1 plot

DV_1 versus Trial plot Overcenter_angle plot

Design study report

9) Close the Information window, the Message window, and the Design Evaluation

Tools dialog box.

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3. Examining the Results of Design Studies

We ran some design studies for all the design variables and provided the results in Table 4.5.

These results are from individual design studies of each design variable, keeping the rest of

the variables fixed at their nominal value.

The results help you determine which design variables you should use for your optimization

study, because they represent a summary of the sensitivity of the clamping force magnitude

to a given change in the geometric location, keeping all other locations fixed.

Table 4.5 Design Studies Results

ADAMS design

variable names:

Design point

locations:

Initial

value:

Sensitivity at initial

value (N/cm):

Apparent

optimal:

DV_1 (POINT x) 0 -82 1

DV_2 (POINT y) 0 56 0

DV_3 (POINT_2 x) 3 142 2.7

DV_4 (POINT_2 y) 3 -440 3.3

DV_5 (POINT_3 x) 2 -23 2.2

DV_6 (POINT_3 y) 8 281 7.6

DV_7 (POINT_5 x) -1 36 -1.1

DV_8 (POINT_5 y) 10 -287 10.5

DV_9 (POINT_6 x) -6 -61 -5.4

DV_10 (POINT_6 y) 5 104 4.5

Parameterization lets you see which design variables have the greatest effect on the

clamping force. In this case, design variables DV_4, DV_6, and DV_8 have the greatest

sensitivity.

4.1.7 Optimizing Your Design

1. Modifying Design Variables

1) On the Build menu, point to Design Variable, and then select Modify.

2) Double-click the first design variable you need to modify, in this case, DV_4.

The Modify Design Variable dialog box appears:


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3) Set the Min. Value and Max. Value, which are the minimum and maximum values

for your first design variable, DV_4, as shown in Table 4.6.

Table 4.6 Design Variable Limits

Design

variable names:

Design point

locations:

Minimum

value:

Maximum

value:

DV_4 POINT_2 y 1 6

DV_6 POINT_3 y 6.5 10

DV_8 POINT_5 y 9 11

4) Select Apply.

5) Right-click the Name text box, point to Variable, and Browse for DV_6.

6) Double-click on DV_6.

7) Type in the minimum and maximum values for DV_6. Make sure the Absolute Min

and Max Values option is selected.

8) Select Apply.

9) Repeat the above three steps for DV_8.

10) After you’ve modified the last design variable, DV_8, select OK.

2. Running an Optimization

1) On the Build menu, point to Measure, and then select Display.

2) Select SPRING_1_MEA_1.

3) Select OK. The SPRING_1_MEA_1 plot appears.

4) On the Build menu, point to Measure, and then select Display.

5) Select overcenter_angle.

6)3 Select OK. The overcenter_angle plot appears.

7) On the Simulate menu, select Design Evaluation.

8) Fill in the dialog boxes as shown below and select Start after selecting Close from the

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two Solver Settings dialog boxes.

The spring force measure plot shows the optimal clamping force as a function of time.


69

The SPRING_1_force versus iteration plot shows how the spring force changed with each

iteration.

The overcenter_angle plot shows the cases in which the angle reached the toggle point.

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4.2 The Front Suspension Design Problem

In this section, you’ll build a Front Suspension model that is required to securely clamp two

halves of large shipping containers together. greška !!!

4.2.1 Introducing the Front Suspension Design Problem

Figure 4.6 shows an illustration of the physical model of the latch.

Figure 4.6 Physical Model of Front Suspension

Figure 4.7 ADAMS/View Front Suspension Model


71

4.2.2 Building Model




dialog box.

2) Replace the contents of the Model name text box with FRONT_SUSP.

3) Select OK.

(2) Setting Up Your Work Environment.


Millimeter, the units of length to Kilogram, Force to Newton, Time to Second, Angle to

Degree, Frequency to Hertz. Select OK.


grid size along X to 750 and Y to 800, and the grid spacing at 50. Select OK.


enter 50. Select OK.


Window.




2) Select the Point tool and click the locations shown in Table 4.7 to place design



Points X Location Y Location Z Location

LCA_outer 0 0 0

UCA_outer 57.25 324.68 14.39

UCA_inner 399.51 391.21 44.90

LCA_inner 485.65 81.27 -86.82

Tie_rod_outer -26.95 100 -107.71

Tie_rod_inner 439.55 181.19 -252.50

Knuckle_inner 18.91 107.24 4.75

Knuckle_outer -235.05 102.81 3.86

3. Creating the Kingpin

1) Select the Cylinder tool .

2) Select New Part.


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4) Click LCA_outer, then UCA_outer to create a Cylinder between the two points.

5) Rename the cylinder part, to Kingpin.

4. Creating the UCA


2) Select New Part.


4) Click UCA_outer, then UCA_inner to create a Cylinder between the two points.

5) Rename the cylinder part, to UCA.

6) Select the Sphere tool .

7) Select Add to Part.

8) In the Radius text box, enter 25.

9) Click UCA, then UCA_outer to create a Sphere.

5. Creating the LCA

1) Select the Cylinder tool.

2) Select New Part.


4) Click LCA_outer, then LCA_inner to create a Cylinder between the two points.

5) Rename the cylinder part, to LCA.




9) Click LCA, then LCA_outer to create a Sphere.

6. Creating the Pull_arm


2) Select New Part.


4) Click Knuckle_inner, then Tie_rod_outer to create a Cylinder between the two

points.

5) Rename the cylinder part, to Pull_arm.

7. Creating the Tie_rod


2) Select New Part.


4) Click Tie_rod_outer, then Tie_rod_inner to create a Cylinder between the two

points.

5) Rename the cylinder part, to Tie_rod.



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9) Click Tie_rod, then Tie_rod_outer and Tie_rod_inner to create two Spheres.

8. Creating the Knuckle


2) Select New Part.


4) Click Knuckle_outer, then Knuckle_inner to create a Cylinder between the two

points.

5) Rename the cylinder part, to Knuckle.

9. Creating the Wheel


2) Select New Part.

3) In the Radius text box, enter 375, in the Length text box, enter 215.

4) Click Knuckle_outer, then Knuckle_inner to create a Cylinder between the two

points.

5) Rename the cylinder part, to Wheel.

6) Select the Fillet tool


8) Click one side of the wheel, and then press right_mouse_button to finish. Repeat the

other side of the wheel.

10. Creating the Test_Patch

1) Select the Point tool .

2) Select Add to Part and Don’t Attach.

3) Creating Design Points: POINT_1 (-350,-320,-200).


5) Select New Part.

6) In the Length, Height, Depth text box, enter 500, 45, 400.

7) Click POINT_1, to create a Box.



10) In the Radius text box, enter 30, in the Length text box, enter 350.

11) Click BOX: PART_1, and then click the CM of the box to create a Cylinder.

12) Rename the part, to Test_Pacth.

11. Creating the Spring


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2) Select Add to Part and Don’t Attach.

3) Creating Design Points: Spring_lower (174.6, 347.85, 24.85).


5) Select Add to Ground and Don’t Attach.

6) Creating Design Points: Spring_upper (174.6, 637.89, 24.85).


8) In the K, C text box, enter 129.8, 6000.

9) Click Spring_lower and Spring_upper, to create a Spring.

12. Creating the Spherical Joint

1) Select the Spherical Joint tool .

2) Select the construction method 2 Bod - 1 Loc, and Normal To Grid.

3) Select the UCA and the Kingpin, and then click the point: UCA_outer, to create the

construction joint between the UCA and the Kingpin.

4) Select the Spherical Joint tool again.

5) Place spherical joints at the following locations using the construction method 2 Bod -


Between the LCA and the Kingpin at LCA_outer.

Between the Tie_rod and the Pull_arm at Tie_rod_outer.

6) Select the Spherical Joint tool again.

7) Select the construction method 1 Location, and Normal To Grid.

8) Click the point: Tie_rod_inner, to create the construction joint between the Tie_rod

and the Ground.

13. Creating the Fixed Joint

1) Select the Fixed Joint tool .

2) Select the construction method 2 Bod - 1 Loc, and Normal To Grid.

3) Select the Pull_arm and the Kingpin, and then click the point: Knuckle_inner, to

create the construction joint between the Pull_arm and the Kingpin.

4) Select the Fixed Joint tool again.

5) Place spherical joints at the following locations using the construction method 2 Bod -


Between the Knuckle and the Kingpin at Knuckle_inner.

Between the Wheel and the Knuckle at Knuckle_inner.

14. Creating the Revolute Joint

1) Click Front_View tool .

2) Select the Revolute Joint tool .

3) Select the construction method 1 Location and Normal To Grid.


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4) Click the point: UCA_inner, to create the revolute joint.

5) Select Edit in the main menu: Click Modify. The modify dialog box appears. Click

(Change Position). The move object dialog box appears. In the Rotate text box, enter 5,

then click . Close the dialog.

6) Repeat 1)—3).

7) Click the point: LCA_inner, to create the revolute joint.

8) Select Edit in the main menu: Click Modify. The modify dialog box appears. Click

(Change Position). The move object dialog box appears. In the Rotate text box, enter

10, then click . Close the dialog.

15. Creating the Translational Joint

1) Select the Translational Joint tool .

2) Select the construction method 1 Location and Pick Feature.

3) Select the Test_Patch.cm, to create the construction joint between the Test_Patch

and the Ground.

16. Creating the Inplane Joint Primitive

1) Select the Inplane Joint Primitive tool .

2) Select the construction method 2 Bodies-1 Location and Pick Geometry Feature.

3) Select the Wheel and the Test_patch, and then click the point: Test_Patch.cm, to

create the construction joint between the Test_Patch and the Ground.

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17. Saving Your Database

File Save Datebase As.

4.2.3 Testing the Front Suspension

1. Adding a Translational Joint Motion

1) Select the Translational Joint Motion tool .

2) Select the Translational Joint between the Wheel and the Test_patch, to create the

Translational Joint Motion (TRANS_MOTION_1).

3) Select Edit in the main menu: Click Modify. The modify dialog box appears.

Click Impose Motion. The Constraint Modify Motion Generator dialog box appears. In

the F(time) text box, enter 100*sin(360d*time), then click OK.


77

2. Simulating the Motion of Your Model


2) Set up a simulation with an end time of 1 second and 100 steps.



3. Creating a Measure on the Kingpin_Inclination

1) From the Build menu, point to Measure, point to Function, and then select New. The

Function Builder dialog box appears.

2) In the Measure Name text box, enter the measure name as Kingpin_Inclination.

Units select angle, then edit the function expression of Kingpin_Inclination with Function

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Builder.

The function expression of Kingpin_Inclination:

ATAN(DX(.FRONT_SUSP.Kingpin.MARKER_2, .FRONT_SUSP.

Kingpin.MARKER_1)/DY(.FRONT_SUSP. Kingpin.MARKER_2, .FRONT_SUSP.

Kingpin.MARKER_1))

Fig. The curve of the Kingpin_Inclination vs time

4. Creating a Measure on the Kingpin_Caster_Angle



2) In the Measure Name text box, enter the measure name as Caster_Angle. Units

select angle, then edit the function expression of Caster_Angle with Function Builder.

The function expression of Caster_Angle:

ATAN(DZ(.FRONT_SUSP.Kingpin.MARKER_2, .FRONT_SUSP.

Kingpin.MARKER_1) / DY(.FRONT_SUSP. Kingpin.MARKER_2, .FRONT_SUSP.

Kingpin.MARKER_1))

5. Creating a Measure on the Front_Wheel Camber_Angle


79



2) In the Measure Name text box, enter the measure name as Camber_Angle. Units

select angle, then edit the function expression of Camber_Angle with Function Builder.

The function expression of Camber_Angle:

ATAN(DY(.FRONT_SUSP.Knuckle.MARKER_1, .FRONT_SUSP.

Knuckle.MARKER_2) / DX(.FRONT_SUSP.Knuckle.MARKER_1, .FRONT_SUSP.

Knuckle.MARKER_2))

6. Creating a Measure on the Front_Wheel Toe_Angle



2) In the Measure Name text box, enter the measure name as Toe_Angle. Units select

angle, then edit the function expression of Toe_Angle with Function Builder.

The function expression of Toe_Angle:

ATAN(DZ(.FRONT_SUSP. Knuckle.MARKER_1, .FRONT_SUSP.

Knuckle.MARKER_2) /DX(.FRONT_SUSP. Knuckle.MARKER_1, .FRONT_SUSP.

Knuckle.MARKER_2))

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7. Creating a Measure on the Sideways_Displacement of the Wheel

Creating Marker Points on the Wheel: Wheel.MARKER_5, modify the position to (-150,

-270, 0). Creating Marker Points on the ground: ground_MARKER_6, modify the position

to (-150, -270, 0).



2) In the Measure Name text box, enter the measure name as Sideways_Displacement.

Units select Length, then edit the function expression of Sideways_Displacement with

Function Builder.

The function expression of Sideways_Displacement:

DX (.FRONT_SUSP.Wheel.MARKER_5, .FRONT_SUSP.ground.MARKER_6)

8. Creating a Measure on the Wheel_Travel



2) In the Measure Name text box, enter the measure name as Wheel_Travel. Units

select Length, then edit the function expression of Wheel_Travel with Function Builder.

The function expression of Wheel_Travel:

DY(.FRONT_SUSP.Wheel.MARKER_5, .FRONT_SUSP.ground.MARKER_6)


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9. Creating curves on the Front Suspension characteristic

1) On the Review menu, select Postprocessing or press F8.

ADAMS/View launches ADAMS/PostProcessor (see Figure 4.5), a post-processing

tool that lets you view the results of simulations you performed.

2) At the bottom left of the dashboard, set Source to Measures.

3) From the Simulation list, select test_dat.

4) At the bottom right of the dashboard, set Independent Axis to Data.

A browser, named Independent Axis Browser, appears. It lets you select data for the

horizontal axis.

5) Select Kingpin_Inclination.

6) Select OK.

7) From the dashboard, from the Measure list, select Wheel_Travel, for the vertical axis

data.

8) Select Add Curves to add the new data to the plot.

ADAMS displays the plot of the two measures as shown next:

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Figure 4.8 The curve of Kingpin_Inclination vs Wheel_Travel

Figure 4.9 The curve of Caster_Angle vs Wheel_Travel

Figure 4.10 The curve of Front_Wheel Camber_Angle vs Wheel_Travel


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Figure 4.11 The curve of Front_Wheel Toe_Angle vs Wheel_Travel

Figure 4.12 The curve of Sideways_Displacement vs Wheel_Travel

4.3 The Full Vehicle Design Problem

4.3.1 Creating Chassis Model




dialog box.

2) Replace the contents of the Model name text box with JEEP.

3) Select OK.

(2) Setting Up Your Work Environment.


Millimeter, the units of length to Kilogram, Force to Newton, Time to Second, Angle to

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Degree, Frequency to Hertz. Select OK.


grid size along X to 2000 and Y to 1000, and the grid spacing at 50. Select OK.


enter 50. Select OK.


Window.




2) Select the Point tool , to create design point: Vehicle_CM (0, 600, 0), which are

Add to Ground and Don’t Attach.

3. Creating Chassis

Select the Sphere tool , select New Part. In the Radius text box, enter 50. Click

Vehicle_CM, to create a Cylinder. Rename the cylinder part, to Chassis.

Place the cursor over the part containing the geometry and hold down the right mouse

button. Point to the name of the geometry that you want to modify and then select Modify.

The Modify Body dialog box appears as shown next.

In the Category box, select Mass Properties. In the Define Mass By box, select User

Input. In the Mass text box, enter 2010. In the Ixx, Iyy, Izz text box, enter 1.06E+009,

2.28E+009, 2.18E+009. Select OK.


85

4.3.2 Creating Front Suspension Model


Select the Point tool and click the locations shown in Table 4.8 to place design




Left_LCA_outer -1339.243 270.315 697.432

Left_UCA_outer -1324.849 594.992 640.183

Left_UCA_inner -1295.861 666.706 316.702

Left_LCA_inner -1428.932 327.896 192.048

Left_Tie_rod_outer -1512.765 363.009 724.270

Left_Tie_rod_inner -1594.556 444.195 257.770

Left_Knuckle_inner -1334.488 377.557 678.522

Left_Wheel_center -1335.000 375.000 825.000

Right_LCA_outer -1339.243 270.315 -697.432

Right_UCA_outer -1324.849 594.992 -640.183

Right_UCA_inner -1295.861 666.706 -316.702

Right_LCA_inner -1428.932 327.896 -192.048

Right_Tie_rod_outer -1512.765 363.009 -724.270

Right_Tie_rod_inner -1594.556 444.195 -257.770

Right_Knuckle_inner -1334.488 377.557 -678.522

Right_Wheel_center -1335.000 375.000 -825.000

2. Creating Front Suspension

Select the Cylinder tool . Select New Part. In the Radius text box, enter 20. Click

Left_LCA_outer and Left_UCA_outer to create a Cylinder between the two points.

Rename the cylinder part, to Left_Kingpin.


Left_UCA_outer and Left_UCA_inner to create a Cylinder between the two points.

Rename the cylinder part, to Left_UCA. Select the Sphere tool . Select Add to Part. In

the Radius text box, enter 25. Click Left_UCA, then Left_UCA_outer, to create a Sphere.


Left_LCA_outer and Left_LCA_inner to create a Cylinder between the two points.

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Rename the cylinder part, to Left_LCA. Select the Sphere tool . Select Add to Part. In

the Radius text box, enter 25. Click Left_LCA, then Left_LCA_outer, to create a Sphere.


Left_Knuckle_inner and Left_Tie_rod_outer to create a Cylinder between the two points.

Rename the cylinder part, to Left_Pull_arm.


Left_Tie_rod_outer and Left_Tie_rod_inner to create a Cylinder between the two points.

Rename the cylinder part, to Left_Tie_rod. Select the Sphere tool . Select Add to Part.

In the Radius text box, enter 20. Click Left_Tie_rod, then Left_Tie_rod_outer and

Left_Tie_rod_inner to create two Spheres.


Left_Wheel_outer and Left_Knuckle_inner to create a Cylinder between the two points.

Rename the cylinder part, to Left_Knuckle.


Right_LCA_outer and Right_UCA_outer to create a Cylinder between the two points.

Rename the cylinder part, to Right_Kingpin.


Right_UCA_outer and Right_UCA_inner to create a Cylinder between the two points.

Rename the cylinder part, to Right_UCA. Select the Sphere tool . Select Add to Part.

In the Radius text box, enter 25. Click Right_UCA, then Right_UCA_outer, to create a

Sphere.


Right_LCA_outer and Right_LCA_inner to create a Cylinder between the two points.

Rename the cylinder part, to Right_LCA. Select the Sphere tool . Select Add to Part.

In the Radius text box, enter 25. Click Right_LCA, then Right_LCA_outer, to create a

Sphere.


Right_Knuckle_inner and Right_Tie_rod_outer to create a Cylinder between the two

points. Rename the cylinder part, to Right_Pull_arm.


Right_Tie_rod_outer and Right_Tie_rod_inner to create a Cylinder between the two

points. Rename the cylinder part, to Right_Tie_rod. Select the Sphere tool . Select

Add to Part. In the Radius text box, enter 20. Click Right_Tie_rod, then

Right_Tie_rod_outer and Right_Tie_rod_inner to create two Spheres.



87

Right_Wheel_outer and Right_Knuckle_inner to create a Cylinder between the two

points. Rename the cylinder part, to Right_Knuckle.

Figure 4.13 The body model of the chassis and the front suspension

3. Creating the Constraint Joint

Select the Spherical Joint tool . Select the constraint method 2 Bod-1 Loc, and

Normal To Grid. Select the Left_UCA and the Left_Kingpin, and then click the point:

Left_UCA_outer, to create the constraint joint between the Left_UCA and the

Left_Kingpin.

Select the Spherical Joint tool again. Place spherical joints at the following locations

using the constraint method 2 Bod - 1 Loc, and Normal To Grid:

Between the Left_LCA and the Left_Kingpin at Left_LCA_outer.

Between the Left_Tie_rod and the Left_Pull_arm at Left_Tie_rod_outer.

Select the Fixed Joint tool . Select the constraint method 2 Bod-1 Loc, and Normal

To Grid. Select the Left_Pull_arm and the Left_Kingpin, and then click the point:

Left_Knuckle_inner, to create the constraint joint between the Left_Pull_arm and the

Left_Kingpin.

Select the Fixed Joint tool again. Select the constraint method 2 Bod-1 Loc, and Normal

To Grid, to create the constraint joint between the Left_Knuckle and the Left_Kingpin at

Left_Knuckle_inner.

On the File menu, select Settings. Click Working Grid. In the Set Location box, select

Pick, click design point: Left_UCA_outer. In the Set Orientation box, select Global YZ.

Click Right_View tool .

Select the Revolute Joint tool . Select the constraint method 2 Bod-1 Loc and

Normal To Grid, Select the Left_UCA and the Chassis, and Click the point: Left_UCA_

inner, to create the revolute joint.

On the File menu, select Edit. Click Modify. Click (Change Position). In the

Rotate text box, enter 5, then click . Close the dialog.

Select the Revolute Joint tool . Select the constraint method 2 Bod-1 Loc and

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88

Normal To Grid, Select the Left_LCA and the Chassis, and Click the point: Left_LCA_

inner, to create the revolute joint. On the File menu, select Edit. Click Modify. Click

(Change Position). In the Rotate text box, enter 10, then click . Close the dialog.

Repeat above steps, to create the revolute joint between the right bodies of the front

suspension.


Select the Point tool . Select Add to Part and Don’t Attach. Creating Design Points:

Left_Spring_lower (-1314.390, 620.866, 523.473) on the Left_UCA.


Left_Spring_upper (-1314.390, 910.866, 523.473) on the Chassis.

Select the Spring tool . In the K, C text box, enter 129.8, 6000. Click Left_Spring_

lower and Left_Spring_upper, to create the left spring of the front suspension.


Right_Spring_lower (-1314.390, 620.866, -523.473) on the Right_UCA.


Right_Spring_upper (-1314.390, 910.866, -523.473) on the Chassis.

Select the Spring tool . In the K, C text box, enter 129.8, 6000. Click Right_Spring_

lower and Right_Spring_upper, to create the right spring of the front suspension.

Figure 4.14 The model of the chassis and the front suspension

4.3.3 Creating Steering System Model





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Pitman_arm_pivot -1624.0 451.0 172.5

Idler_arm_pivot -1624.0 451.0 -172.5

Lower_sector_shaft_point -1444.0 451.0 172.5

Idler_arm_center -1444.0 451.0 -172.5

Steering_shaft_pivot -1232.0 562.0 230.5

Steering_wheel_pivot -873.5 678.6 260.0

Steering_wheel_center -260.0 1033.2 260.0

2. Creating Steering System


Left_Tie_rod_inner and Pitman_arm_pivot to create a Cylinder between the two points.

Rename the cylinder part, to Center_link (left ).

Select the Cylinder tool . Select Add to Part. In the Radius text box, enter 15.

Select body: Center_link, select point: Pitman_arm_pivot and Idler_arm_pivot, to create

the middle part of the Center_link.

Select the Cylinder tool . Select Add to Part. In the Radius text box, enter 15.

Select body: Center_link, select point: Idler_arm_pivot and Right_Tie_rod_inner, to

create the right part of the Center_link.


Pitman_arm_pivot and Lower_sector_shaft_point to create a Cylinder between the two

points. Rename the cylinder part, to Pitman_arm.


Idler_arm_pivot and Idler_arm_center to create a Cylinder between the two points.

Rename the cylinder part, to Idler_arm.

Figure 4.15 The model of the steering trapezium


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90

Lower_sector_shaft_point and Steering_shaft_pivot to create a Cylinder between the two

points. Rename the cylinder part, to Steering_gear.


Steering_shaft_pivot and Steering_wheel_pivot to create a Cylinder between the two

points. Rename the cylinder part, to Steering_shaft.


Steering_wheel_center and Steering_wheel_pivot to create a Cylinder between the two

points. Rename the cylinder part, to Steering_Wheel.

On the File menu, select Settings. Click Working Grid. The Working Grid Settings

dialog box appears. In the Set Location box, select Pick, click design point:

Steering_wheel_center. In the Set Orientation box, select Z-Axis, pick the axis direction

of the Steering_wheel cylinder as to Z-Axis of Working Grid.

Select the Torus tool . Select Add to Part. In the Inner Radius and Outer Radius

text box, enter 12 and 190. Select body: Steering_Wheel, select point: Steering_Wheel_

center, to create another part of the Steering_Wheel.

On the File menu, select Settings. Click Working Grid. Pick Polar. In the Circle

Spacing and Radial Increments text box, enter 10 and 3. Select OK.

Select the Cylinder tool . Select Add to Part. In the Length and Radius text box,

enter 190 and 8. Select body: Steering_Wheel, select center point: Steering_Wheel_center,

to create three cylinders.

Figure 4.16 The model of the steering system



91

Select the Hooke Joint tool . Select the constraint method 2 Bod-1 Loc and Pick

Feature. Select the Left_Tie_rod and the Center_link, and then click the point:

Left__Tie_rod_inner, Hooke Joint orientation: axis direction of the Left_Tie_rod and the

Center_link, to create the constraint joint between the Left_Tie_rod and the Center_link.

Setting up Working Grid orientation: Global XZ direction. Click Top View Select the

Revolute Joint tool . Select the constraint method 2 Bod-1 Loc and Normal To Grid,

Select the Center_link and the Pitman_arm, and Click the point: Pitman_arm_pivot, to

create the revolute joint.

Setting up Working Grid orientation: Global XZ direction. Click Top View. Select the


Select the Pitman_arm and the Chassis, and Click the point: Lower_sector_shaft_point,

to create the revolute joint between the Pitman_arm and the Chassis.

Select the Spherical Joint tool . Select the constraint method 2 Bod-1 Loc and

Normal To Grid. Select the Center_link and the Idler_arm, and then click the point:

Idler_arm_pivot, to create the constraint joint between the Center_link and the

Idler_arm.


Feature. Select the Idler_arm and the Chassis, and then click the point:

Idler_arm_center, Hooke Joint orientation: plus (or minus) axis direction of the

Idler_arm, to create the constraint joint between the Idler_arm and the Chassis.


Feature. Select the Right_Tie_rod and the Center_link, and then click the point:

Right_Tie_rod_inner, Hooke Joint orientation: axis direction of the Right_Tie_rod and

the Center_link, to create the constraint joint between the Right_Tie_rod and the

Center_link.

Select the Revolute Joint tool . Select the constraint method 2 Bod-1 Loc and Pick

Feature, Select the Steering_gear and the Chassis, and Click the design point:

Steering_gear.CM, Revolute Joint orientation: axis direction of the Steering_gear

cylinder, to create the revolute joint between the Steering_gear and the Chassis.

Select the Coupler Joint tool . Select two types of Constraint Joint: the Revolute

Joint between the Steering_gear and the Chassis, the Revolute Joint between the

Pitman_arm and the Chassis. The Revolute Joint between the Pitman_arm and the

Chassis is the Coupler Joint. The Scale of the Coupler Joint is modified to 14.

Select the Constant-Velocity Joint tool . Select the constraint method 2 Bod-1 Loc

and Pick Feature. Select the Steering_wheel and the Steering_shaft, and then click the

sd

Pencil

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92

point: Steering_wheel_pivot, Constant-Velocity Joint orientation: axis direction of the

Steering_wheel cylinder and the Steering_shaft, to create the constraint joint between the

Steering_wheel and the Steering_shaft.

Select the Constant-Velocity Joint tool . Select the constraint method 2 Bod-1 Loc

and Pick Feature. Select the Steering_gear and the Steering_shaft, and then click the

point: Steering_shaft_pivot, Constant-Velocity Joint orientation: axis direction of the

Steering_shaft and the Steering_gear cylinder, to create the constraint joint between the

Steering_shaft and the Steering_gear.

Select the Cylindrical Joint tool . Select the constraint method 2 Bod-1 Loc and

Pick Feature. Select the Steering_wheel and the Chassis, and then click the point:

Steering_wheel.CM, Cylindrical Joint orientation: axis direction of the Steering_wheel

cylinder, to create the constraint joint between the Steering_wheel and the Chassis.

4.3.4 Creating Rear Suspension Model






Left_RCA_pivot 689.37 375.0 363.22

Left_RCA_outer 1265.0 375.0 695.56

RL_Wheel_center 1265.0 375.0 825.0

Right_RCA_pivot 689.37 375.0 -363.22

Right_RCA_outer 1265.0 375.0 -695.56

RR_Wheel_center 1265.0 375.0 -825.0

2. Creating Rear Suspension


Left_RCA_pivot and Left_RCA_outer to create a Cylinder between the two points.

Rename the cylinder part, to Left_RCA.

Select the Cylinder tool . Select Add to Part. In the Radius text box, enter 25. Click

Left_RCA, then RL_Wheel_center and Left_RCA_outer, to create Left_RCA.


Right_RCA_pivot and Right_RCA_outer to create a Cylinder between the two points.


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Rename the cylinder part, to Right_RCA.

Select the Cylinder tool . Select Add to Part. In the Radius text box, enter 25. Click

Right _RCA, then RR_Wheel_center and Right _RCA_outer, to create Right _RCA.

Figure 4.17 The model of the rear suspension


Setting up Working Grid orientation: Global XY direction. Click Top View Select the


Select the Left_RCA and the Chassis, and Click the point: Left_RCA_pivot, to create the

revolute joint. Modify the position of the Revolute Joint: rotation to 300.

Figure 4.18 Creating the Revolute Joint

Setting up Working Grid orientation: Global XY direction. Click Top View Select the


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94

Select the Right_RCA and the Chassis, and Click the point: Right_RCA_pivot, to create

the revolute joint. Modify the position of the Revolute Joint: rotation to 300.



RL_Spring_lower (1070.42, 375.0, 583.22) on the Left_RCA.


RL _Spring_upper (1070.42, 641.0, 583.22) on the Chassis.

Select the Spring tool . In the K, C text box, enter 160.2, 6000. Click RL_Spring_

lower and RL_Spring_upper, to create the left spring of the rear suspension.


RR_Spring_lower (1070.42, 375.0, -583.22) on the Right_RCA.


RR_Spring_upper (1070.42, 641.0, -583.22) on the Chassis.

Select the Spring tool . In the K, C text box, enter 160.2, 6000. Click RR_Spring_

lower and RR_Spring_upper, to create the right spring of the rear suspension.

Figure 4.19 The model of the rear suspension spring

4.3.5 Creating Tire and Road

1. Creating Tire Property File

The five tire models were provided in the ADAMS/View, Table 4.11 shows the models.

The TIRE statement has five required arguments, the tire id, the J marker id, the tire mass,

the tire inertia properties, and the associated tire property file.


95

Table 4.11 Overview of Tire Models

Tire type Data required Applicability

Fiala

(Default)

Basic tire properties Handling analysis

Pure slip

University of

Arizona (UA)

Basic tire

properties

Handling analysis

Comprehensive slip

Smithers Coefficients from

fitted tire test data

Handling analysis

Pure slip

Delft Coefficients from

fitted tire test data

Handling analysis

Comprehensive slip

User Defined User User

Default Dynamic Analysis Tire Model

An enhanced version of the so-called Fiala model is available as a default in

ADAMS/Solver. The default tire model calculates tire forces in the longitudinal, lateral, and

vertical directions as well as aligning moment and rolling resistance in response to slip

angle, slip ratio and normal deflection. Camber thrust is not modeled. While rather simple,

this model is capable of providing reliable results for situations not involving

comprehensive slip, i.e., situations where longitudinal slip and lateral slip are not present

simultaneously. This model is automatically invoked by ADAMS/Solver during a dynamic

simulation involving tires translating at moderate to fast rates.

UA-Tire Dynamic Analysis Model

The UA-Tire model developed by Nikravesh and Gim at the University of Arizona, is part

of the optional ADAMS/Tire module. The UA-Tire model computes normal, longitudinal,

and lateral forces as well as aligning torque and rolling resistance under comprehensive slip

conditions. These forces and moments are determined by explicit formulations which are

analytically derived depending on the coupled properties of slip ratio, slip angle, inclination

angle, normal deflection, and other dynamic tire properties.

The UA-Tire model is much more comprehensive and accurate than the simpler Fiala model.

It always provides much better results for aligning moments than the Fiala model.

Additionally, in situations of comprehensive slip, the UA-Tire model provides much more

realistic values for the other forces and torques.

Smithers Dynamic Analysis Tire Model

The Smithers tire model is part of the optional ADAMS/Tire module. This model is also

referred to as the BNPS or Bakker-Nyborg-Pacejka-Smithers model. The Smithers model

computes the lateral force and the aligning moment from the slip angle, inclination angle,

vertical force, and data provided by Smithers Scientific Services. The Fiala tire model

4 Examples

96

computes the other tire forces and torques. The Smithers model comes complete with three

sample tire property files, which you can use until you obtain the specific tire property files

for your perspective tires.

DELFT Dynamic Tire Model

The DELFT tire model is part of the optional ADAMS/Tire module. This model was

developed by TNO Road-Vehicle Research Institute in the Netherlands. It is a Pacejka

―magic formula‖ tire model. The model computes lateral, longitudinal, and vertical forces

and the aligning moment from fitted coefficients TNO provides.

User-Defined Tire Models

You have the option of defining your own tire model. A user-written subroutine, TIRSUB,

is provided to facilitate this. Instantaneous tire kinematic contact properties and tire material

properties are provided as input to TIRSUB. In addition, users can use the UPARAMETER

and USTRINGS arguments to pass real values and character strings to TIRSUB. TIRSUB

should return to ADAMS/Solver the three forces and the three torques acting at the contact

patch in the instantaneous SAE coordinate system. ADAMS/Solver transfers the forces and

torques to the tire hub center and apply them.

The UA tire model was selected in the example. The tires are P215/80R16 meridian tire.

The tire property shown in Table 4.12.

Table 4.12 P215/80R16 Meridian Tire Property

Model R1

R1 /mm

R2

R2 /mm

CNORMAL

Cz /(N/mm)

CSLIP

Cs /(N/mm)

CALPHA

Cα /(N/rad)

Analytical 375 107.5 261.3 30000 46000

CGAMMA

Cγ /(N/rad)

CRR

f

RDR

U0

0

U1

1

4000 0.015 0.75 0.94 0.74

CALPHA: The tire’s cornering stiffness: the partial derivative of lateral force (Fy) with

regard to slip angle (α) at zero slip angle. CALPHA = Cα = r1*r2. CALPHA should have

units of force per radian or degree.

CGAMMA: The tire’s camber stiffness: the partial derivative of lateral force (Fy) with

regard to inclination (camber) angle at zero camber angle. Note that CGAMMA = Cγ =

r1*r2.

CNORMAL: The tire’s vertical stiffness: the partial derivative of vertical force (Fz) with

regard to ire vertical penetration (such as deflection) at zero vertical penetration. Note that

CNORMAL = Cz = r1*r2.

CRR: Specifies the conversion factor and the rolling resistance moment coefficient. Note

that CRR = Cr = r1*r2. CRR should have units of length.


97

CSLIP: The tire’s longitudinal slip stiffness: the partial derivative of longitudinal force (Fx)

with regard to longitudinal slip (s) at zero longitudinal slip. Note that CSLIP=Cs = r1*r2.

CSLIP should have units of force.

R1: Specifies the conversion factor and the unloaded tire radius, that is, radial distance from

the tire center to the crown of the tread.

R2: Specifies the conversion factor and the carcass radius of a toroidal (or doughnut shaped)

tire. This is equal to one half the greatest distance from one sidewall to the other, when

measured along an axis parallel to the tire spin axis.

Figure 4.20 Analytical and Geometrical Representation of Tire

RDR: Specifies the tire radial damping ratio(ζ). RDR is the ratio of tire damping to critical

damping.

U0: Specifies the tire/road coefficient of friction at zero slip and represents the ―sticking‖ or

―static‖ friction coefficient.

U1: Specifies the tire/road coefficient of friction for the full slip case and represents the

―sliding‖ or ―kinetic‖ friction coefficient.

The tire property file (jeep_tire.tpf) appears as shown next.

! ----------------------

! | TIRE_PROPERTY_FILE |

! ----------------------

MODEL=

ANALYTICAL

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98

! ANALYTICAL PARAMETERS BLOCK

R1 (undeflected outside tire radius)

1 375

R2 (idealized toroidal cross section carcass radius)

1 107.5

CN (vertical stiffness at zero deflection)

1 261.3

CSLIP (longitudinal stiffness at zero slip ratio)

1 30000

CALPHA (lateral stiffness due to slip angle at zero slip angle)

0.01745 46000

CGAMMA (lateral stiffness due to inclination angle at zero inclination angle)

0.01745 4000

CRR (rolling resistance moment)

1.00 5.625

RDR (vertical damping ratio)

0.75

U0 (maximum friction coefficient, friction coefficient at zero slip)

0.94

U1 (minimum friction coefficient, friction coefficient at full slip)

0.75

2. Creating Road Data File

The road data file (jeep_road.rdf) appears as shown next.

! ----------------------

! | ROAD DATA FILE |

! ----------------------

! jeep road file - flat

METHOD

GENDATA

!

! Conversion factors

!

X_SCALE

1.0

Y_SCALE

1.0

Z_SCALE


99

1.0

!

! Road origin is located at the following global coordinates in the data set.

!

ORIGIN

0 0 0

UP

0.0,1.0,0.0

!

! Road coordinate system is oriented with respect to the global origin

! by the following transformation matrix.

!

ORIENTATION

1 0 0

0 1 0

0 0 1

!

!coordinates for the node points on road

!

NODES

4

1 200000.0 0.0 -20000.0

2 -500000.0 0.0 -20000.0

3 200000.0 0.0 400000.0

4 -500000.0 0.0 400000.0

!

! Connectivity of node points defining the triangular element

!

ELEMENTS

2

1 2 3 1.0 1.0

2 3 4 1.0 1.0

3. Creating Tire and Road

1) From the Main Toll menu, point to Force Database, point to Tire. The Create Tire

Force dialog box appears.

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100

2) Select Tire Type: UA Tire.

3) In the Attachment Marker text box, enter .JEEP.Left_Knuckle.MARKer_11, it is

the marker of Left_Knuckle in the Left_Wheel_center.

4) In the Tire Mass text box, enter 29.2.

5) In the Tire Inertia Moments text box, enter 5.002E+005, 5.002E+005, 6.904E+005.

6) In the Tire Property File text box, enter jeep_tire.tpf and path.

7) In the Road Data File text box, enter jeep_road.rdf and path.

8) In the Tire Width text box, enter 215.

9) Select OK, to create the left tire of front suspension.

10) Repeat above steps, to create the right tire of front suspension and the tires of rear

suspension.


101

Figure 4.21 shows the model of tires. Figure 4.22 shows the full vehicle model.

Figure 4.21 The model of Tire

Figure 4.22 Full vehicle models

4.3.6 Testing the Full Vehicle

1. Creating Motion and Torque

Select the Rotational Joint Motion tool . Select the Cylindrical Joint between the

Steering_wheel and the Chassis, to create the Rotational Joint Motion on the

Steering_wheel. Modify the motion equation: step(time, 1,0,2,100d), see Fig.4.23.

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102

Figure 4.23 Joint Motion Dialog Box

Select the Torque tool . Select Two Bodies, see Figure 4.23. Select the Left_RCA

as master body, then select the TIRE_3 as slave body, select design point of the

Left_RCA_outer as master point, select design point of the RL_Wheel_center as slave

point, to create the drive torque on the Left Tire. Modify the torque equation: step(time,

0,0,1,-11000)+step(time,60,-30000,120,-150000), see Fig.4.25.

Figure 4.24 Figure 4.25 Modify Torque Dialog Box

Follow above steps to create the drive torque on the Right Tire between the Right_RCA


103

and the TIRE_4.

2. Creating curves on the vehicle characteristic



2) In the Measure Name text box, enter the measure name as Radius. Units select

Length(m), then edit the function expression of Radius with Function Builder.

The function expression of Radius:

(VM(.jeep.chassis.cm)/WY(.jeep.chassis.cm))/1000



4) In the Measure Name text box, enter the measure name as Velocity. Units select

Length(m), then edit the function expression of Velocity with Function Builder.

The function expression of Velocity:

SQRT(VX(.JEEP.Chassis.cm)**2+VZ(.JEEP.Chassis.cm)**2)*3.6/1000

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104

3. Simulation


2) Set up a simulation with an end time of 120 second and Step Size of 0.01.



The curves on the vehicle characteristic appear during the simulation, as shown next:

Figure 4.26 The curve of the Kingpin_Inclination vs time

Figure 4.27 The curve of the velocity vs time


105

Figure 4.28 The curve of the Kingpin_Inclination vs velocity

Figure 4.29 The motion trace of the vehicle mass center

5 Introduce ADAMS/Car

106

Section II - ADAMS/Car


This chapter introduces you to ADAMS/Car and explains how you can benefit from using it.

It also explains how you can learn more about ADAMS/Car and introduces the tutorials that

we’ve included in this guide to help you become familiar with ADAMS/Car.

5.1 What is ADAMS/Car?

ADAMS/Car is a specialized environment for modeling vehicles. It allows you to create

virtual prototypes of vehicle subsystems, and analyze the virtual prototypes much like you

would analyze the physical prototypes.

The ADAMS/Car model hierarchy is comprised of the following components, which are

stored in databases:

Templates - Are ADAMS/Car models built in ADAMS/Car Template Builder by

users who have expert privileges. Templates are parameterized and generally are

topological representations of vehicle subsystems, which can include front

suspensions, brakes, chassis, and so on.

You save templates in ASCII or binary format.

Subsystems - Are based on ADAMS/Car templates and allow standard users to

change the parametric data of the template. For example, you can change the

location of hardpoints, modify parameter variables, and so on.

You save subsystems in ASCII format.

Assemblies - Are comprised of subsystems that can be grouped together to form

suspension assemblies, full-vehicle assemblies, and so on.

You save assemblies in ASCII format.

ADAMS/Car has two modes:

Standard Interface - You use it when working with existing templates to create and

analyze assemblies of suspensions and full vehicles. Both standard users and expert

users can use ADAMS/Car Standard Interface.

Template Builder - If you have expert user privileges, you use ADAMS/Car

Template Builder to create new templates for use in ADAMS/Car Standard

Interface.


107

When you create a new component in the Template Builder, ADAMS/Car automatically

adds a prefix based on the entity type and the symmetry. ADAMS/Car uses a naming

convention to let you easily determine an entity’s type from the entity’s name.

5.2 What You Can Do with ADAMS/Car

Using ADAMS/Car, you can quickly create assemblies of suspensions and full vehicles,

and then analyze them to understand their performance and behavior.

You create assemblies in ADAMS/Car by defining vehicle subsystems, such as front and

rear suspensions, steering gears, anti-roll bars, and bodies. You base these subsystems on

their corresponding standard ADAMS/Car templates. For example, ADAMS/Car includes

templates for double-wishbone suspension, MacPherson strut suspension, rack-and-pinion

steering, and so on.

If you have expert user privileges, you can also base your subsystems on custom templates

that you create using the ADAMS/Car Template Builder.

When you analyze an assembly, ADAMS/Car applies the analysis inputs that you specify.

For example, for a suspension analysis you can specify inputs to:

Move the wheels through bump-rebound travel and measure the toe, camber, wheel

rate, roll rate, and side-view swing arm length.

Apply lateral load and aligning torque at the tire contact path and measure the toe

change and lateral deflection of the wheel.

Rotate the steering wheel from lock to lock and measure the steer angles of the

wheels and the amount of Ackerman, that is, the difference between the left and

right wheel steer angles.

Based on the analysis results, you can quickly alter the suspension geometry or the spring

rates and analyze the suspension again to evaluate the effects of the alterations. For example,

you can quickly change a rear suspension from a trailing-link to a multi-link topology to see

which yields the best handling characteristics for your vehicle.


108

Once you complete the analysis of your model, you can share your work with others. You

can also print plots of the suspension characteristics and vehicle dynamic responses. In

addition, you can access other users’ models without overwriting their data.

5.3 How You Benefit from Using ADAMS/Car

ADAMS/Car enables you to work faster and smarter, letting you have more time to study

and understand how design changes affect vehicle performance. Using ADAMS/Car you

can:

Explore the performance of your design and refine your design before building and

testing a physical prototype.

Analyze design changes much faster and at a lower cost than physical prototype

testing would require. For example, you can change springs with a few mouse

clicks instead of waiting for a mechanic to install new ones in your physical

prototype before re-evaluating your design.

Vary the kinds of analyses faster and more easily than if you had to modify

instrumentation, test fixtures, and test procedures.

Work in a more secure environment without the fear of losing data from instrument

failure or losing testing time because of poor weather conditions.

Run analyses and what-if scenarios without the dangers associated with physical

testing.


109

6 Introducing Analyses in ADAMS/Car

ADAMS/Car allows you to quickly and easily analyze suspensions and full vehicles under

various conditions. The following sections introduce you to running analyses.

6.1 About ADAMS/Car Analyses

Using ADAMS/Car to analyze a virtual prototype is much like ordering a test of a physical

prototype. When ordering a test in ADAMS/Car, you specify the following:

The virtual prototype to be tested - You specify the virtual prototype by opening

or creating an assembly that contains the appropriate components, or subsystems,

that make up the prototype. For example, you create suspension assembly

containing suspension and steering subsystems and the suspension test-rig.

ADAMS/Car contains suspension and full-vehicle test rigs.

The kind of analysis you’d like performed - You specify the test or analysis by

selecting one from the ADAMS/Car Simulate menu. There are two major types of

analyses: suspension and full-vehicle.

The analysis inputs to be used - You specify the inputs to the analysis by typing

them directly into an analysis dialog box or by selecting a loadcase file that contains

the desired inputs from an ADAMS/Car database.

After specifying the prototype assembly and its analysis, ADAMS/Car, like your company’s

testing department, applies the inputs that you specified and records the results. To

understand how your prototype behaved during the analysis, you can plot the results. After

viewing the results, you might modify the prototype and analyze it again to see if your

modifications improve its behavior.

Each kind of analysis that you perform requires a minimum set of subsystems. For example,

a suspension analysis requires one suspension subsystem. A full-vehicle analysis requires

front and rear suspension subsystems, front and rear wheel subsystems, one steering

subsystem, and one body subsystem. Before you can create an assembly and perform an

analysis in ADAMS/Car, you must open or create the minimum set of subsystems required.

6.2 Types of Analyses

There are two types of analyses that you can run in ADAMS/Car: suspension analyses and

full-vehicle analyses. To run full-vehicle analyses, you must have purchased the

ADAMS/Car Vehicle Dynamics package.


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1. About Suspension Analyses

ADAMS/Car lets you analyze and view virtual prototypes of suspensions and steering

subsystems. Using ADAMS/Car, you can:

Easily modify the topology and the properties of the components of your

suspension.

Run a standard set of suspension and steering maneuvers.

Visualize suspension characteristics through plots.

For a suspension analysis, you can specify inputs to:

Move the wheels through bump-rebound travel and measure the toe, camber, wheel

rate, roll rate, side-view swing-arm length, and other characteristics.

Apply lateral load and aligning torque at the tire contact path and measure the toe

change and lateral deflection of the wheel.

Rotate the steering wheel from lock to lock and measure the steer angles of the

wheels and the amount of Ackerman, which is the difference between the left and

right wheel steer angles.

Based on ADAMS/Car results, you can alter the suspension geometry or spring rates and

analyze the suspension again to evaluate the effects of the alterations.

2. About Full-Vehicle Analyses

ADAMS/Car lets you analyze virtual prototypes of full vehicles. Using ADAMS/Car, you

can:

Easily modify the geometry and the properties of the components of your

subsystems.

Select from a standard set of vehicle maneuvers to evaluate handling characteristics

of your virtual prototype.

View the vehicle states and other characteristics through plots.

6.3 Introducing Suspension Analyses

You can test suspensions to determine their kinematic and compliance characteristics by

performing wheel travel, static load, and steering analyses. This chapter explains how to run

suspension analyses and describes each type of suspension analysis you can run.

6.3.1 Suspension Analysis Process

You perform a suspension analysis to learn how a suspension controls the wheel motions

and transmits load from the wheels to the chassis. To perform a suspension analysis, you

first create or open a suspension assembly that contains the selected subsystems and the test

rig. You then specify ranges of vertical wheel travel, steering travel, and static tire contact


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patch loads and the number of solution steps.

During the analysis, the test rig articulates the suspension assembly in the specified number

of steps and applies the inputs you specified. At each step, ADAMS/Car calculates over 38

suspension characteristics, such as toe angle, camber angle, track change, wheel base

change, wheel rate (vertical stiffness), fore-aft wheel center stiffness, and so on. You can

plot these characteristics and use them to determine how well the suspension controls the

motions of the wheels.

Figure 6.1 shows an overview of the process.

Figure 6.1 Suspension Analysis Process

A suspension analysis in ADAMS/Car is a quasi-static equilibrium analysis.

6.3.2 Suspension Assembly Roles

To create a suspension assembly, you can select any subsystem that has either a suspension

or a steering major role. A major role defines the primary function of the subsystem.

6.3.3 Setting Suspension Parameters

Before you submit a suspension analysis, you need to set the suspension parameters that

ADAMS/Car uses when calculating suspension characteristics. These parameters describe

the vehicle in which you wish to use the suspension. ADAMS/Car uses, for example, the

parameters wheelbase, cg_height, and sprung mass to calculate the fore-aft weight transfer

during braking and acceleration.

Once you set the vehicle parameters in an ADAMS/Car session, ADAMS/Car uses those

settings for all suspension analyses until you reset the parameters.

To set parameters:

(1) From the Simulate menu, point to Suspension Analysis, and then select Set

Suspension Parameters.

(2) Enter the desired parameter values, and then select OK.

6.3.4 Submitting Suspension Analyses

You submit an analysis by selecting a specific analysis from the Simulate menu and then


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entering the vertical wheel travel and other parameters needed to control the analysis. You

can also select one or more loadcase files (.lcf) from an ADAMS/Car database. Loadcase

files contain the vertical wheel travel and other parameters needed to control a suspension

analysis. If you regularly perform several kinds of suspension analyses using the same

ranges of travel, you should consider creating loadcase files for these. You can then submit

all the analyses without having to reenter travel parameters each time. Actually, as you

perform an analysis for which you did not create a loadcase file, ADAMS/Car temporarily

creates one for you and deletes it after the analysis.

Note: All suspension analyses in ADAMS/Car are quasi-static equilibrium analyses.

1. Specifying Number of Steps

As you submit a suspension analysis, you specify the number of steps in the analysis. The

number of steps is the number of solution steps from a lower bound to an upper bound. For

example, for an opposite wheel travel analysis, if you specify five steps and -100 mm

rebound and 100 mm jounce, ADAMS/Car temporarily creates a loadcase file that contains

left vertical wheel displacement inputs of -100, -60, -20, 20, 60, and 100 mm and right

vertical wheel displacement inputs of 100, 60, 20, -20, -60, and -100 mm as shown in figure

6.1:

Figure 6.2 Number of Inputs to Steps

2. Types of Suspension Analyses

The suspendsion analyses include:

The types of analyses that you can run on a suspension are:

(1) Wheel Travel Analyses:

A wheel travel analysis allows you to look at how the characteristics of a suspension change


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throughout the vertical range of motion of the suspension.

You can perform three types of wheel travel analyses, as explained in the next sections. As

a minimum, all wheel travel analyses require a suspension subsystem. These analyses can

also include a steering subsystem.

Parallel Wheel Travel Analysis

Opposite Wheel Travel Analysis

Single Wheel-Travel Analysis

Parallel Wheel Travel Analysis: A parallel wheel travel analysis keeps the left wheel and

right wheel heights equal, while moving the wheels through the specified bump and

rebound travel.

Opposite Wheel Travel Analysis: An opposite wheel travel analysis moves the left and

right wheel through equal, but opposite, vertical amounts of travel to simulate body roll.

The left and right wheels move over the specified jounce and rebound travel, 180 degrees

out of phase with each other. You specify the parameters to define the vertical wheel travel

and the fixed steer value when you submit the analysis.

Single Wheel-Travel Analysis: A single wheel-travel analysis moves one wheel, either the

right or left, through the specified jounce and rebound travel while holding the opposite

wheel fixed in a specified position.

(2) Roll & Vertical Force Analysis

A roll and vertical force analysis sweeps the roll angle while holding the total vertical force

constant. The total vertical force is the sum of the vertical forces on the left and right

wheels.

In contrast to the opposite wheel travel analysis, the roll and vertical force analysis allows

the wheels to seek their own vertical position.

(3) Steering Analysis

A steering analysis steers the wheels over the specified steering wheel angle or rack travel

displacement from the upper to the lower bound. A steering analysis requires a suspension

subsystem and a steering subsystem.

(4) Static Load Analysis

Depending on the type of load you input, the static load analysis applies static loads to the

spindle and the tire patches between the specified upper and lower load limits. A static load

analysis requires a suspension subsystem.

(5) External-File Analyses

There are two types of external-file analyses: loadcase and wheel-envelope analysis.


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6.4 Introducing Full-Vehicle Analyses

6.4.1 Full-Vehicle Analysis Process

You can take previously created suspension subsystems and integrate them with other

subsystems to create a full-vehicle assembly. You can then perform various analyses on the

vehicle to test the design of the different subsystems and see how they influence the total

vehicle dynamics. You can also examine and understand the influence of component

modifications, including changes in spring rates, damper rates, bushing rates, and antirollbar

rates, on the total vehicle dynamics.

Figure 6.3 shows an overview of the process.

Figure 6.3 Full-Vehicle Analysis Process

6.4.2 About the Full-Vehicle Analyses

You can perform several types of full-vehicle analyses using ADAMS/Car. All of the

analyses, except for the data-driven analyses, use the .__MDI_SDI_TESTRIG, and are

therefore based on the Driving Machine.

The next sections describe the different types of analyses you can perform:

Open-Loop Steering Analyses

Cornering Analyses

Straight-Line-Behavior Analyses

Course Analyses

Driver-Control-File-Driven Analysis

Quasi-Static Analyses

Data-Driven Analysis

ADAMS/Driver Analyses


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1. Open-Loop Steering Analyses

ADAMS/Car provides a wide range of open-loop steering analyses. In open-loop steering

analyses, the steering input to your full vehicle is a function of time.

The open-loop steering analyses include:

Drift - In a drift analysis, the vehicle reaches a steady-state condition in the first ten seconds.

A steady-state condition is one in which the vehicle has the desired steer angle, initial

throttle, and initial velocity values. In seconds 1 through 4 of the analysis, ADAMS/Car

ramps the steering angle/length from an initial value to a desired value. It then ramps the

throttle from zero to the initial throttle value in seconds 5 through 10. Finally, it ramps the

throttle value up to the desired value from a time of 10 seconds to the desired end time.

Fish-Hook - You use this analysis is to evaluate dynamic roll-over vehicle stability. The

test is usually performed by driving at a constant speed, putting the vehicle in neutral,

turning in one direction to a preselected steering wheel angle, and then turning in the

opposite direction, to a final preselected steering wheel angle. You can define the duration

of the step functions and the initial and final turn direction.

Impulse steer - In an impulse steer analysis, the steering demand is a force/torque,

single-cycle, sine input. The steering input ramps up from an initial steer value to the

maximum steer value. You can run with or without cruise control. The purpose of the test is

to characterize the transient response behavior in the frequency domain. Typical metrics are:

lateral acceleration, and vehicle roll and yaw rate, both in time and frequency domain.

Ramp steer - You use this analysis to obtain time-domain transient response metrics. The

most important quantities to be measured are: steering wheel angle, yaw angle speed,

vehicle speed and lateral acceleration. During a ramp steer analysis, ADAMS/Car ramps up


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the steering input from an initial value at a specified rate.

Single lane-change analysis - During a single lane-change analysis, the steering input goes

through a complete sinusoidal cycle over the specified length of time. The steering input

can be:

Length, which is a motion applied to the rack of the steering subsystem.

Angle, which is angular displacements applied to the steering wheel.

Force applied to the rack.

Torque applied to the steering wheel.

Step steer - The purpose of this analysis is to obtain time-domain transient response metrics.

The most important quantities to be measured are: steering wheel angle, yaw angle speed,

vehicle speed and lateral acceleration. During a step steer analysis, ADAMS/Car increases

the steering input from an initial value to a final value over a specified time.

Swept-sine steer - Sinusoidal steering inputs at the steering wheel let you measure

frequency-response vehicle characteristics. This provides a basis for evaluating a vehicle

transitional response, the intensity and phase of which varies according to the steering

frequency. The most important factors for this evaluation are: steering wheel angle, lateral

acceleration, yaw speed, and roll angle. During a swept-sine steer analysis, ADAMS/Car

steers the vehicle from an initial value to the specified maximum steer value, with a given

frequency. It ramps up the frequency of the steering input from the initial value to the

specified maximum frequency with the given frequency rate.

2. Cornering Analyses

You use Driving Machine cornering analyses to evaluate your vehicle’s handling and

dynamic response. Cornering analyses combine open- and closed-loop controllers of the

steering, throttle, brake, gear, and clutch signals to perform complex analyses on your

vehicle.

The cornering analyses include:


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Braking in a turn - This is one of the most critical analyses encountered in everyday

driving. The purpose of this analysis is to examine path and directional deviations caused by

sudden braking during cornering. Typical results collected from the braking-in-turn test

include lateral acceleration, variations in turn radius, and yaw angle as a function of

longitudinal deceleration.

In a braking-in-turn analysis, the Driving Machine drives your full vehicle down a straight

road, turns onto a skidpad, and then accelerates to achieve a desired lateral acceleration.

Once the desired lateral acceleration is reached, the Driving Machine holds the longitudinal

speed and radius constant for a time to let any transients settle. Then, it locks the steering

wheel and brakes your full vehicle at a constant deceleration rate. It maintains the

deceleration rate for a given duration or until the vehicle speed drops below 2.5

meters/second.

You can use the plot configuration, mdi_fva_bit.plt, in the shared ADAMS/Car database to

generate the plots that are typically of interest for this type of analysis.

Constant radius cornering - For constant radius cornering analysis, the Driving Machine

drives your full vehicle down a straight road, turns onto a skidpad, and then gradually

increases velocity to build up lateral acceleration. One common use for a constant radius

cornering analysis is to determine the understeer characteristics of the full vehicle.

Cornering with steer release - The vehicle performs a dynamic constant-radius cornering

to achieve the prescribed conditions (radius and longitudinal velocity or longitudinal

velocity and lateral acceleration). After the steady state prephase, the steering wheel

closed-loop signal is released, simulating a release of the steering wheel. The analysis

focuses primary on the path deviation, yaw characteristics, steering wheel measurements,

roll angle, roll rate, and side-slip angle.

Lift-off turn-in - The purpose of this analysis is to examine path and directional deviations

caused by suddenly lifting the throttle pedal during cornering and applying an additional

ramp steering input.

Power-off during cornering - A steering controller drives the vehicle around a skid pad.

When the prescribed conditions are achieved, the steering wheel is locked and the throttle

demand is decreased to zero. This analysis allows you to determine the power-off effect on

course holding and directional behavior of a vehicle whose steady-state circular path is

disturbed by throttle power-off.

Typical results collected from the power-off cornering analysis include variations in the

heading direction and longitudinal deceleration, as well as sideslip angle, yaw angle and

gradient. Optionally, the clutch can be depressed during the throttle lift-off. In this case, you

specify the duration that is takes to depress the clutch.

3. Straight-Line-Behavior Analyses

The analyses based on the Driving Machine focus on the longitudinal dynamics of the


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vehicle. ADAMS/Car uses open- and closed-loop longitudinal controllers to drive your

vehicle model.

The straight-line-behavior analyses include:

Acceleration test - Ramps the throttle demand from zero at your input rate (open loop) or

you can specify a desired longitudinal acceleration (closed loop). You can specify either

free or locked steering. An acceleration test analysis helps you study the anti-lift and

anti-squat properties of a vehicle.

Braking - Ramps the brake input from zero at your input rate or lets you specify a

longitudinal deceleration (closed loop). You can also specify either free or locked steering.

The braking test analysis helps you study the brake-pull anti-lift and anti-dive properties of

a vehicle.

Power-off straight line - This analysis allows you to examine operating behavior and

directional deviations caused by suddenly lifting off the throttle pedal during a straight-line

analysis. Typical results collected from the power off straight-line analysis include

variations in heading direction and longitudinal deceleration. You can control the analysis

using the Driving Machine. Optionally, you can depress the clutch during the throttle lift-off.

In this case, you specify the duration that it takes to depress the clutch.

4. Course Analyses

Course analyses are based on the Driving Machine and are of a course-following type, such

as ISO-lane change.

In an ISO-lane change analysis, the Driving Machine drives your full vehicle through a lane

change course as specified in ISO-3888: Double Lane Change. You specify the gear

position and speed at which to perform the lane change. The analysis stops after the vehicle

travels 250 meters; therefore, the time to complete the lane change depends on the speed

you input.

5. Driver-Control-File-Driven Analysis (DCF Drive…)

The driver-control-file-driven analysis lets you run a analysis described in an existing driver

control file (.dcf). For the format and content of .dcf files. Having direct access to .dcf files

allows you to easily perform nonstandard analyses on your full-vehicle assembly because

all you have to do is to generate a new .dcf file describing the analysis.

6. Quasi-Static Analyses

Quasi-static analyses find dynamic equilibrium solutions for your full vehicle at increasing,

successive values of lateral acceleration. Quasi-static analyses, in contrast to open-loop and

closed-loop analyses, do not include transient effects and solve very quickly. For example,

in a quasi-static analysis, a change in lateral acceleration from 0.1g to 0.5g does not show

the lateral acceleration or yaw rate overshoot that a similar openloop and closed-loop

analysis might show.

Quasi-static analyses use either the .__MDI_DRIVER_TESTRIG or the .__MDI_SDI_


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TESTRIG.

(1) Setting up Quasi-Static Analyses

Before you submit a quasi-static analysis, you must set up the assembly to run quasi-static

analyses.

You set up a quasi-static analysis by selecting the Setup button from the constant radius

cornering or constant-velocity cornering dialog boxes. ADAMS/Car then adds additional

modeling elements that do not exist by default in the standard MDI full-vehicle assemblies.

The additional elements reference information provided by communicators that are defined

in the standard templates distributed with ADAMS/Car. The communicators are:

Body template: cos_body communicator: part communicator

Front/rear suspension template:

co[lr]_suspension_upright: part communicator

co[lr]_suspension_mount: part communicator

Steering template:

cos_steering_wheel_joint: joint communicator

Powertrain template:

co[lr]_output_torque: force communicator

cos_drive_torque_left: solver variable communicator

cos_drive_torque_right: solver variable communicator

If you are using standard ADAMS/Car templates but have removed some of the

communicators, or if you built your own templates that do not include those communicators,

as part of the setup procedure, ADAMS/Car prompts you to identify various elements in

your assembly. You can avoid being prompted for these elements by including the

communicators in the appropriate templates.

(2) Constant-Radius Cornering Analysis

You perform a constant radius cornering analysis to evaluate your full vehicle’s understeer

and oversteer characteristics. The constant radius cornering analysis holds the turn radius

constant and varies the vehicle velocity to produce increasing amounts of lateral

acceleration. You can use the plot configuration file mdi_fva_ssc.plt in the shared

ADAMS/Car database to generate the plots that are typically of interest for this analysis.

Before submitting a constant radius cornering analysis, you must select the Setup button to

set up your full-vehicle assembly for a quasi-static analysis.

(3) Constant-Velocity Cornering Analysis

You perform a constant velocity cornering analysis to evaluate your full vehicle’s

understeer and oversteer characteristics. The constant velocity cornering analysis holds the

vehicle velocity constant and varies the turn radius to produce increasing amounts of lateral

acceleration. The input parameters for this analysis are the same as the steady-state

cornering analysis except that the vehicle longitudinal velocity is specified instead of the


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turn radius. You can use the plot configuration file mdi_fva_ssc.plt in the shared car

database to generate the plots that are typically of interest for this analysis.

Before submitting a constant velocity cornering analysis, you must select the Setup button

to set up your full-vehicle assembly for a quasi-static analysis.

(4) Force-Moment Analysis

You perform a force-moment analysis maneuver to evaluate the stability and handling

characteristics of your vehicle model. ADAMS/Car drives the vehicle at constant

longitudinal speed and performs a series of simulations at different side-slip and steer

angles. The simulation represents a typical test in which the vehicle is constrained on a

model flat-belt tire tester. The testing method is based on the assumption that most of the

stability and control characteristics can be obtained from a study of the steady-state force

and moments acting on the vehicle.

The analysis consists of a series of quasi-static steady-state cornering analyses performed at

different vehicle side-slip angles and at a different steer angle. Usual results of a quasistatic

force-moment analysis can be presented in tabular form, or as diagrams and plots

representing the computed forces and moments from the simulated test.

Before you can submit a force-moment analysis, you must set up your vehicle for a

quasistatic analysis.

7. Data-Driven Analysis

You define the inputs for a data-driven analysis in a driver loadcase file (dri.). The driver

loadcase file contains the time/distance open-loop signals for steering, throttle, brake, clutch,

and gear. This is the only analysis that requires the .__MDI_DRIVER_TESTRIG and is

based on a loadcase file.

8. ADAMS/Driver Analyses

ADAMS/Driver enables you to add the control actions of a human driver to your fullvehicle

simulations. These actions include steering, braking, throttle position, gear shifting and

clutch operation.

Using ADAMS/Driver, you can extend the set of full-vehicle events available in

ADAMS/Car. ADAMS/Car simulates the vehicle on a user-defined track representing a

road.

ADAMS/Driver analyses use the .__MDI_DRIVER_TESTRIG or the .__MDI_SDI_

TESTRIG.


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7 Creating and Simulating Suspensions

7.1 Starting ADAMS/Car Standard Interface

To start ADAMS/Car in the Windows environment:

1 From the Start menu, point to Programs, point to ADAMS, point to ACar, and then

select ADAMS - Car (view).

The Welcome dialog box appears on top of the ADAMS/Car main window.

2 Do one of the following:

If the Welcome dialog box contains the options Standard Interface and Template

Builder, select Standard Interface, and then select OK.

If the Welcome dialog box does not contain any options, then ADAMS/Car is

already configured to run in standard mode. Select OK.

7.2 Creating Suspension Assemblies

In this section, you work with a suspension and steering assembly from two subsystems: a

suspension subsystem and a steering subsystem. You create the suspension subsystem using

the standard double-wishbone template. You don’t need to create the steering subsystem.

Instead, you can open an existing subsystem that we’ve provided.

After creating and opening the subsystems, you create an assembly that contains the

subsystems and a test rig.

7.2.1 Creating a New Front Suspension Subsystem

You create the front suspension subsystem based on a double-wishbone design stored in the

standard template named _double_wishbone.tpl, and then save it.


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After you create the subsystem, you save it in an ADAMS/Car database. When you save a

subsystem, ADAMS/Car stores it in the database designated as the default writable database.

Initially, the private database is the default writable database, but as you become more

familiar with ADAMS/Car, you can change your writable database. Later, when you are

sure the design is complete or ready for review, you can have your database administrator

save the file in a shared database or allow others to access it from your private database.

1. Creating the front suspension subsystem:

1) Start ADAMS/Car in Starting ADAMS/Car Standard Interface.

2) From the File menu, point to New, and then select Subsystem.

The New Subsystem dialog box appears.

3) In the Subsystem Name text box, enter UAN_FRT_SUSP.

4) Set Minor Role to front. A minor role defines the subsystem’s function and its

placement in the assembly (for example, front or rear). In this case, you select front because

you are creating a front suspension.

5) Right-click the Template Name text box, point to Search, and then select the

acar_shared database.

The File Selection dialog box appears.

6) Double-click _double_wishbone.tpl.

The Template Name text box now contains the file _double_wishbone.tpl and an alias

to its directory path.

7) Verify that Translate from default position is not selected.

8) Select the Comment tool .

The Modify Comment dialog box appears.

9) In the Comment Text text box, enter Baseline UAN Front Suspension.


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10) Select OK.

11) Select OK again.

ADAMS/Car creates the suspension subsystem using the default data contained in the

template and displays it as shown next:

Figure 7.1 Suspension Subsystem

2. To save the suspension subsystem

■ From the File menu, select Save.

ADAMS/Car saves the subsystem in your default writable database, which might be your


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private database.

7.2.2 Creating a Suspension and Steering Assembly

In this section, you create a new suspension assembly and add to it a steering subsystem.

To create the suspension and steering assembly:

1) From the File menu, point to New, and then select Suspension Assembly.

The New Suspension Assembly dialog box appears.

2) In the Assembly Name text box, enter my_assembly.

3) Click the folder icon next to Suspension Subsystem.

The name of the suspension subsystem you just created appears.

4) Select Steering Subsystem.

5) Right-click the Steering Subsystem text box, point to Search, and then select the


The File Selection dialog box appears.

6) Double-click MDI_FRONT_STEERING.sub.

The Steering Subsystem text box now contains MDI_FRONT_STEERING.sub and an

alias to its directory path.

Note that by default ADAMS/Car selects a test rig for the assembly, ._MDI_

SUSPENSION_TESTRIG.

7) Select OK.

The Message window appears, informing you of the steps ADAMS/Car takes when creating

the assembly.

ADAMS/Car displays the suspension and steering assembly in the main window, as shown

in Figure 7.2.


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Figure 7.2 Suspension and Steering Assembly

8) Select Close, to close the Message window.

7.3 Performing a Baseline Parallel Wheel Travel Analysis

You now perform a parallel wheel travel analysis on the suspension and steering assembly,

and then plot and view the results.

7.3.1 Defining Vehicle Parameters

Before performing a suspension analysis, you must specify several parameters about the

vehicle in which you intend to use the suspension and steering subsystems. These

parameters include the vehicle’s wheel base and sprung mass, whether or not the suspension

is front- or rear-wheel drive, and the braking ratio. For this analysis, you enter the

parameters to indicate front-wheel drive and a brake ratio of 64% front and 36% rear.

To define vehicle parameters:

1) From the Simulate menu, point to Suspension Analysis, and then select Set


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Suspension Parameters.

The Suspension Analysis: Setup Parameters dialog box appears. It contains default settings

to help you quickly set up a suspension analysis.

2) Set up the analysis as follows:

Suspension Assembly: my_assembly

Tire Model: User Defined

Tire Unloaded Radius: 300

Tire Stiffness: 200

Wheel Mass: 1.0

Sprung Mass: 1400

CG Height: 300

Wheelbase: 2765

Drive Ratio: 100

All driving force is applied to the front wheels.

Brake Ratio: 64

The brake ratio value indicates the % of braking force that is applied to the front

brakes.

3) Select OK.

7.3.2 Performing the Analysis

Now that you’ve defined the vehicle parameters, you can run the parallel wheel travel

analysis. During the analysis, the test rig applies forces or displacements, or both, to the

assembly, as defined in a loadcase file. For this analysis, ADAMS/Car generates a

temporary loadcase file based on the inputs you specify.

This parallel wheel travel analysis moves the wheel centers from -100 mm to +100 mm

relative to their input position, while holding the steering fixed. During the wheel motion,

ADAMS/Car calculates many suspension characteristics, such as camber and toe angle,

wheel rate, and roll center height.

To perform the analysis:

1) From the Simulate menu, point to Suspension Analysis, and then select Parallel

Wheel Travel.



Output Prefix: baseline

Number of Steps: 15

Mode of Simulation: interactive

Bump Travel: 100

Rebound Travel: -100


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Travel Relative To: Wheel Center

Steering Input: Angle


4) In the Comment Text text box, enter Baseline Parallel Wheel Travel Analysis.

5) Select OK.

6) Select OK again.

7) When the analysis is complete, select Close.

7.3.3 Animating the Results

In this section, you view the analysis you just ran. ADAMS/Car has already loaded the

animation and graphic files for you.

To animate the results:

1) From the Review menu, select Animation Controls.

2) Select the Play tool .

ADAMS/Car animates the motion of the suspension analysis. Notice that the

suspension moves from rebound (down), to bump (up), and that the steering wheel does not

rotate.

3) When the animation is complete, close the dialog box.

7.4 Performing a Baseline Pull Analysis

You can now perform a baseline pull analysis to study the pull on the steering wheel. You

will use the results of this pull analysis as the baseline against which you compare the

results of another pull analysis that you perform after you modify the location of the

steering axis. By comparing the results from the two analyses, you can determine if the

modifications were successful.

7.4.1 Defining a Loadcase File

Before you can run the baseline pull analysis, you need to create a loadcase file to drive the

analysis. In the loadcase file, you specify the unequal braking forces to simulate braking on

a split-μ surface and the beginning, or upper, and ending, or lower, steering wheel angles.

To calculate the unequal brake forces, we assume that the vehicle is braking at a rate of 0.5

g’s deceleration, with a 64% front and 36% rear brake ratio, a vehicle mass of 1,400 kg, and

the front braking force split 55% left and 45% right. Based on these assumptions, the total


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front braking force is:

1400 kg × 0.5 g × 9.81 m/s2/g × 0.64 = 4395 N

From this, the left and right braking forces are:

■ Left braking force = 0.55 × 4395 N or 2417 N

■ Right braking force = 4395 N - 2417 N or 1978 N

You can use these calculations to define the loadcase file.

To define a loadcase file:

1) From the Simulate menu, point to Suspension Analysis, and then select Create

Loadcase.

Note: If Select Loadcase Type is not set to Static Load, your dialog box will look slightly

different. Make sure you select Static Load first, and then proceed to fill in the dialog box.

2) Fill in the dialog box as shown next, and then select OK.

ADAMS/Car creates the loadcase file, named brake_pull.ldf, and stores it in your private

database. It stores the loadcase file as text (ASCII) and you can print it or edit it manually.

To create the loadcase file, ADAMS/Car takes the parameters that you entered and

generates a table of input values. For the parameters that you entered, ADAMS/Car

generates a table that varies steering wheel angle from -180 to 180 in 15 steps, while


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holding the braking forces constant.

Table 7.1 shows the loadcase file values:

Table 7.1 Loadcase File for Pull Analysis

Steering Wheel Left Brake Force Right Brake Force

-180 2417 1978

-156 2417 1978

-132 2417 1978

-108 2417 1978

-84 2417 1978

-60 2417 1978

-36 2417 1978

-12 2417 1978

12 2417 1978

36 2417 1978

60 2417 1978

84 2417 1978

108 2417 1978

132 2417 1978

156 2417 1978

180 2417 1978

7.4.2 Performing the Analysis

You can now use the loadcase file that you just created to perform an analysis that

determines the pull characteristics of the suspension and steering assembly.

To perform the pull analysis:

1) From the Simulate menu, point to Suspension Analysis, and then select External

Files.



Output Prefix: baseline

Mode of Simulation: interactive

Loadcase Files: mdids://private/loadcases.tbl/brake_pull.lcf

3) Make sure Load Analysis Results is selected.

4) Clear the selection of Create Analysis Log File.



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6) In the Comment Text text box, enter Baseline Pull Analysis.

7) Select OK.

8) Select OK again.

7.4.3 Animating the Results

In this section, you view an animation of the analysis ADAMS/Car just performed.

To animate the results:


2) Select the Play tool.

ADAMS/Car animates the turning motion of the steering subsystem. You should see the

wheels turn as the steering wheel rotates. The wheel centers should not move vertically.

3) Close the Animation Controls dialog box.

7.5 Modifying the Suspension and Steering Subsystem

For a double-wishbone suspension, the line running from the lower spherical joint to the

upper spherical joint defines the steering axis or kingpin axis. If these joints move outboard

while the rest of the suspension geometry remains unchanged, the scrub radius is decreased.

In the suspension subsystem that you created, two hardpoint pairs define the locations of

these joints:

hpl_lca_outer and hpr_lca_outer, where lca_outer means lower control arm outer,

and the prefix hpl means hardpoint left and the prefix hpr means hardpoint right.

hpl_uca_outer and hpr_uca_outer, where uca_outer means upper control arm outer

and the prefix hpl means hardpoint left and the prefix hpr means hardpoint right.

Hardpoints define independent locations in space.

7.5.1 Modifying Hardpoint Locations

You must first display a table that contains data about the current locations that the

hardpoints define. You can then modify the hardpoint locations. You only need to indicate

how you want to move the left hardpoints in each pair, and ADAMS/Car modifies the right

hardpoints accordingly.

To view hardpoint locations:

1) From the View menu, select Subsystem.

The Display Subsystem dialog box appears, already containing the subsystem

my_assembly.UAN_FRT_SUSP.

2) Select OK.


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3) From the Adjust menu, point to Hardpoint, and then select Table.

The Hardpoint Modification Table appears. It displays the locations of all the hardpoints in

the assembly. You can use this table to display and modify the locations of any of the

hardpoints.

The locations of the paired hardpoints differ only by the sign of the Y location. Therefore,

the paired hardpoints are symmetrical about the X-Z plane. With symmetrical hardpoints,

you only need to move one of the hardpoints, not both. If you want, however, you can break

the symmetry and move only one of the hardpoints of a symmetrical pair.

To see the symmetry, select left or right from the bottom of the Hardpoint Modification

Table.

To modify the hardpoints:

1) Click the cell common to hpl_lca_outer and loc_y.

2) Change the existing value to -775. This moves the hardpoint point 25 mm outboard.

3) Scroll the table window down until you see the hardpoint hpl_uca_outer.

4) Click the cell common to hpl_uca_outer and loc_y.

5) Change the existing value to -700. This moves the hardpoint 25 mm outboard.

6) Select Apply.

ADAMS/Car changes the hardpoint locations of the two hardpoints and their symmetrical

right pairs.

7) Close the dialog box.

7.5.2 Saving the Modified Subsystem

In this section, you save the subsystem you just modified.

To save the subsystem:

1) From the File menu, select Save.

Before saving the file, ADAMS/Car asks you if you want to create a backup copy of

the file.

2) Select No. This overwrites the subsystem file in your default writable database.

ADAMS/Car saves the subsystem file that you created.

7.6 Performing an Analysis on the Modified Assembly

To determine how the modifications to the suspension subsystem changed the pull on the

steering wheel, you perform a pull analysis on the modified suspension and steering

assembly. You can use the same loadcase file that you created in Defining a Loadcase File.

To perform the analysis:

1) From the Simulate menu, point to Suspension Analysis, and then select External


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Files.

The dialog box displays the appropriate loadcase file.

2) In the Output Prefix text box, enter modified.

3) Select the Comment tool.

4) In the Comment Text text box, enter Steering axis moved 25mm outboard.

5) Select OK.

6) Select OK again.

ADAM/Car analyzes the modified suspension and steering assembly.


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8 Template Builder Tutorial

This chapter guides you through the process of building a template, creating a suspension

subsystem based on the template, and then running various analyses on the subsystem. To

build the template, you must use ADAMS/Car Template Builder.

To learn how to create templates, you create a complete MacPherson front suspension

template, as shown in Figure 8.1. You then build a suspension using the template you

created. Finally, you run kinematic and compliant suspension analyses and compare their

results.

Figure 8.1 MacPherson front suspension template model

8.1 Starting ADAMS/Car Template Builder

In this section, you start the ADAMS/Car Template Builder and begin working in

template-builder mode.

Before you start ADAMS/Car Template Builder, make sure that your private configuration

file, .acar.cfg, shows that you can work in expert-user mode. Your private configuration file


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is located in your home directory.

To check the user mode:

1) In a text editor, such as jot or notepad, open .acar.cfg.

2) Verify that the following line appears as shown:

ENVIRONMENT MDI_ACAR_USERMODE expert

This line sets the user mode for the ADAMS/Car session.

To start ADAMS/Car Template Builder:

1) Start ADAMS/Car Standard Interface, just as you did in Starting ADAMS/Car

Standard Interface.

2) From the Tools menu, select ADAMS/Car Template Builder.

8.2 Creating Topology for Your Template

Before you begin to build your template, you must decide what elements are most

appropriate for your model. You must also decide which geometries seem most applicable

to each part or whether you want any geometry at all. Once you’ve decided, you create a

template and create the basic topology for it. Finally, you assemble the model for analysis.

8.2.1 Creating a Template

You must create a template in which to build suspension parts. You should assign to your

template a major role as a suspension template, because a major role defines the function

the template serves for the vehicle.

To create a template:

1) Start ADAMS/Car Template Builder as explained in Starting ADAMS/Car Template

Builder.

2) From the File menu, select New.

The New Template dialog box appears.

3) In the Template Name text box, enter macpherson.

4) Verify that Major Role is set to suspension.

5) Select OK.

A gravity icon appears in the middle of the ADAMS/Car main window as shown in

Figure 18. If you don’t see a gravity icon, display the main shortcut menu by right-clicking

the main window, and selecting Toggle Icon Visibility. You can also toggle the icon

visibility on and off by placing the cursor in the main window and typing a lowercase v.

6) From the main shortcut menu, select Front Iso and Fit - All. Fit your model to view

whenever you create an entity outside the current view.

The ADAMS/Car main window should look as follows:


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Figure 8.2 Main Window with Gravity Icon Displayed

8.2.2 Building Suspension Parts

You create parts in ADAMS/Car through a three-step process. First, you create hardpoints

that define key locations on the part. Then, you create the actual part. Finally, if you want,

you add geometry to your new part.

You can use one of two methods to create parts in ADAMS/Car:

■ User-entered method lets you manually enter mass properties and material type for a

part.

■ Geometry-based method lets you tell ADAMS/Car to automatically create mass

properties using the geometry and material type that you specify.

1. Creating the Control Arm

The first part you define is the control arm. You begin by building its hardpoints. You can

later modify these hardpoints to determine their effects on your vehicle.

Next, you create the control arm part and specify its coordinate system location and mass

properties.

To complete the creation of the control arm, you create geometry for it. You then define key

locations for that geometry so ADAMS/Car can calculate its mass properties. In this tutorial,

whenever you want ADAMS/Car to calculate mass properties, you select steel as the

material type.

When specifying orientations in ADAMS/Car, you can either enter Euler angles or specify

two direction vectors. In this tutorial, you will just use Euler angles with respect to the

global orientation, which is named the origo marker.

To build the hardpoints:


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1) From the Build menu, point to Hardpoint, and then select New.

The Create Hardpoint dialog box appears.

2) In the Hardpoint Name text box, enter arm_outer.

3) Verify that Type is set to left.

In this tutorial, you set all entities to left. ADAMS/Car automatically creates a

symmetrical pair about the central longitudinal axis.

Note: Depending on how you set up your environment variables, the longitudinal axis can

be any axis. In this tutorial, the longitudinal axis is the x-axis.

4) In the Location text box, enter 0, -700, 0.

5) Select Apply.

ADAMS/Car executes the command, but leaves the Create Hardpoint dialog box open.

6) Repeat Steps 2 through 5 to build the two hardpoints specified in Table 8.1.

Table 8.1 Wheel Carrier Hardpoints

Hardpoint Name: Location:

Arm_front -150,-350,0

Arm_rear 150,-350,0

7) When you’re done creating the hardpoints, close the dialog box.

8) To see all six hardpoints in the main window, see figure 8.3, fit your model to view.


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Figure 8.3 Six hardpoints in the main window

2. To create the control arm part:

1) From the Build menu, point to Parts, point to General Part, and then select New.


ADAMS/Car creates a part coordinate system, also referred to as local part reference frame

(LPRF), at the specified location, but it doesn’t create geometry.


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3. To create the control arm geometry:

1) From the Build menu, point to Geometry, point to Arm, and then select New.

2) Create the control arm as follows:

Arm Name: control_arm

General Part: ._macpherson.gel_control_arm

Coordinate Reference #1: ._macpherson.ground.hpl_arm_outer

Coordinate Reference #2: ._macpherson.ground.hpl_arm_front

Coordinate Reference #3: ._macpherson.ground.hpl_arm_rear

Thickness: 10

3) Select Calculate Mass Properties of General Part.

4) Set Density to Material.

5) Select OK.

ADAMS/Car displays the control arm part. If you want the control arm to be shaded, put

the cursor in the main window and type an uppercase S. This toggles the rendering mode

between shaded and wireframe.

Note: Based on the geometry, the option Calculate Mass Properties of General Part

computes the mass properties for the part, and adds that to the total mass of the part. (You

can have more than one geometry associated with a part.)

8.2.3 Creating the Wheel Carrier

To create the wheel carrier, you must first create three hardpoints that define the location of

the wheel carrier. You then define the wheel carrier part using these hardpoint locations.

Next, you add link geometry to the wheel carrier. When you add the link geometry, you

enter parameters that are similar to those you specified for the arm geometry, except that a

link only requires two coordinate reference points to define its geometry.

1. To create the hardpoints:

1) From the Build menu, point to Hardpoint, and then select New.

2) Create the wheel carrier hardpoints as specified in Table 8.2. Remember that you can

select Apply to execute the command but leave the dialog box open, and select OK to

execute the command and then close the dialog box.

Table 8.2 Wheel Carrier Hardpoints

Hardpoint Name: Location:

Wheel_center 0,-800,100

Strut_lower 0,-650,250

Tierod_outer 150,-650,250


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3) To display the hardpoints in the main window, toggle the icon visibility and fit your

model to view.

Note: Remember that all these hardpoints are left-side hardpoints.

2. To create the wheel carrier part:

1) From the Build menu, point to Parts, point to General Part, and then select Wizard.

2) Create the wheel carrier part as follows:

General Part Name: wheel_carrier

Geometry Type: Arm

Coordinate Reference #1: ._macpherson.ground.hpl_wheel_center

Coordinate Reference #2: ._macpherson.ground.hpl_arm_outer

Coordinate Reference #3: ._macpherson.ground.hpl_strut_lower

Thickness: 10

3) Select OK.

The wizard creates both the part and the geometry.

3. To add the wheel carrier link geometry:

1) From the Build menu, point to Geometry, point to Link, and then select New.

2) Create the wheel carrier part as follows:

Link Name: carrier_link

General Part: ._macpherson.gel_wheel_carrier


Coordinate Reference #2: ._macpherson.ground.hpl_tierod_outer

Radius: 10


4) Select OK.

The template now includes the wheel carrier part and the link geometry.

8.2.4 Creating the Strut

In this section, you create the strut part for your suspension template. Just as you did for the

control arm, you enter the location, orientation, and mass properties for the strut part.

Because the strut geometry would not be visible from inside the damper, you don’t need to

give the strut any geometry.

To define the strut part:


2) Define the strut part as follows:

General Part: strut

Location values: 0, -600, 600

Euler Angles: 0, 0, 0

Mass/Ixx/Iyy/Izz: 1


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3) Select OK.

8.2.5 Creating the Damper

You first create a hardpoint and then use it to define the damper. You then create a damper

that is defined by a property file that we provide for you. Property files define

force-displacement or force-velocity characteristics for springs, dampers, bumpstops,

reboundstops, and bushings. In this case, the property file defines the damper’s

force-velocity curve.

1. To create a hardpoint:

1) Create a hardpoint as follows:

Hardpoint Name: strut_upper

Location: 0, -600, 600

2) Select OK.

2. To create the damper:

1) From the Build menu, point to Forces, point to Damper, and then select New.

2) Create the damper as follows:

Damper Name: damper

I Part: ._macpherson.gel_wheel_carrier

J Part: ._macpherson.gel_strut

I Coordinate Reference: ._macpherson.ground.hpl_strut_lower

J Coordinate Reference: ._macpherson.ground.hpl_strut_upper

3) Select OK.

8.2.6 Defining the Spring

Before you define the spring, you have to create a hardpoint that defines the position of the

lower spring seat. Then, to define the spring, you must specify the following:

Two bodies between which you want the force to act.

Specific location on each body where you want the force to act.

Installed length of the spring, which will be used to derive the design preload on the

spring.

Property file, which contains the free length information, as well as the

force/deflection characteristics.

ADAMS/Car calculates the force exerted by the spring using the following equations:

C = FL - IL + DM(i,j)

Force = -k(C - DM(i,j))

where:

C is a constant.


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FL is the free length of the spring, as defined in the property file.

IL is the defined installed length.

DM(i,j) is the initial displacement between the i and j coordinate reference points. If

you enter a smaller value for DM(i,j), ADAMS/Car calculates an increased preload

for the spring. Conversely, if you enter a larger value, ADAMS/Car calculates a

decreased preload. In this tutorial, you enter the value that ADAMS/Car

automatically calculates for you.

DM(i,j) is the change in the displacement between the i and j coordinate reference

points as the simulation progresses.

Force represents the spring force.

k is the nonlinear spring stiffness derived from the property file.

1. To create a hardpoint for the spring:

1) Create a hardpoint as follows:

Hardpoint Name: spring_lower

Location: 0, -650, 300

2) Select OK.

2. To create the spring:

1) From the Build menu, point to Forces, point to Spring, and then select New.


The template now includes the damper and the spring.

8.2.7 Creating the Tie Rod

You first create a hardpoint and then use it to define the tie rod part.

1. To create a hardpoint:

1) Create a hardpoint with the following specifications:


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Hardpoint Name: tierod_inner

Location: 200, -350, 250

2) Select OK.

2. To create the tie rod part:

1) From the Build menu, point to Parts, point to General Part, and then select Wizard.

2) Create the tie rod part as follows:

General Part Name: tierod

Geometry Type: Link

Coordinate Reference #1: ._macpherson.ground.hpl_tierod_outer

Coordinate Reference #2: ._macpherson.ground.hpl_tierod_inner

Radius: 10

3) Select OK.

The template now includes the tie rod part.

8.2.8 Creating the Toe and Camber Variables

You create variables defining toe and camber angles. Because these variables are commonly

used for suspension analyses, ADAMS/Car creates both of them in one step.

1. To create toe and camber variables:

1) From the Build menu, point to Suspension Parameters, point to Toe/Camber Values,

and then select Set.


8.2.9 Creating the Hub

Before you create the hub part for your template, you must create a construction frame.

Construction frames are ADAMS/Car elements that you use whenever an entity requires

that you specify an orientation in addition to a location.

You create the hub based on the construction frame, and then create geometry for the hub.

1. To create a construction frame:

1) From the Build menu, point to Construction Frame, and then select New.

2) Create a construction frame as follows:


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Construction Frame: hub_bearing

Coordinate Reference: ._macpherson.ground.hpl_wheel_center

Orientation Dependency: Toe/Camber

Toe Parameter Variable: ._macpherson.pvl_toe_angle

Camber Parameter Variable: ._macpherson.pvl_camber_angle

3) Select OK.

2. To create the hub part:


2) Create the hub part as follows:

General Part: hub

Location Dependency: Delta location from coordinate

Coordinate Reference: cfl_hub_bearing

Location values: 0, 0, 0

Orientation Dependency: Delta orientation from coordinate

Construction Frame: cfl_hub_bearing

Orientation: 0, 0, 0

Mass/Ixx/Iyy/Izz: 1

3) Select OK.

3. To create cylinder geometry for the hub:

1) From the Build menu, point to Geometry, point to Cylinder, and then select New.

2) Create the cylinder geometry as follows:

Cylinder Name: hub

General Part: ._macpherson.gel_hub

Construction Frame: ._macpherson.ground.cfl_hub_bearing

Radius: 30

Length in Positive Z: 30

Length in Negative Z: 0

Color: magenta


4) Select OK.

The template now includes the hub.

8.2.10 Creating and Defining Attachments and Parameters

Now that you created all the ADAMS/Car parts, springs, and dampers, you are ready to

define attachments and parameters.

1. Defining the Translational Joint

1) From the Build menu, point to Attachments, point to Joint, and then select New.

2) Create the translational joint as follows:


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Joint Name: strut_joint


J Part: ._macpherson.gel_strut

Joint Type: translational

Coordinate Reference: ._macpherson.ground.hpl_strut_upper

Orientation Dependency: Orient axis along line


Coordinate Reference #2: ._macpherson.ground.hpl_strut_upper

3) Select OK.

2. Defining Control Arm Attachments

To create the mount parts:

1) From the Build menu, point to Parts, point to Mount, and then select New.

2) In the Mount Name text box, enter subframe_to_body.

3) In the Coordinate Reference text box, enter ._macpherson.ground.hpl_arm_front.

4) Verify that From Minor Role is set to inherit.

5) Select OK.

ADAMS/Car creates fixed joints between the mount parts and ground. By default, the

visibility of the fixed joints is turned off.

To create the front bushing for the control arm:

1) From the Build menu, point to Attachments, point to Bushing, and then select New.

2) Fill in the dialog box as shown in figure 8.4, and then select Apply.

To create the control arm revolute joint:

1) Create the control arm revolute joint as follows:

Joint Name: arm_front

I Part: ._macpherson.gel_control_arm

J Part: ._macpherson.mtl_subframe_to_body

Joint Type: revolute

Active: kinematic mode

Coordinate Reference: ._macpherson.ground.hpl_arm_front

Orientation Dependency: Orient axis along line

Coordinate Reference #1: ._macpherson.ground.hpl_arm_front

Coordinate Reference #2: ._macpherson.ground.hpl_arm_rear

2) Select Apply.

To create the control arm spherical joint:

1) Create the control arm spherical joint as follows:

Joint Name: arm_outer


J Part: ._macpherson.gel_control_arm


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Joint Type: spherical

Active: always

Coordinate Reference: ._macpherson.ground.hpl_arm_outer

2) Select OK.

Figure 8.4 Create bushing Attachment dialog box

3. Defining the Strut Attachment

Before you define the strut attachments to the vehicle body, you must define a mount part

for the strut. You then create a bushing for the strut. Next, you create a spherical joint to

replace the strut mount bushing during kinematic analyses.

To define a mount part:

1) Create a mount part as follows:


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Mount Name: strut_to_body


From Minor Role: inherit

2) Select OK.

To create a bushing for the strut:

Create the bushing as shown next, and then select OK.

To create a spherical joint for the strut:

1) Create the spherical joint as follows:

Joint Name: strut_upper

I Part: ._macpherson.gel_strut

J Part: ._macpherson.mtl_strut_to_body


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Active: kinematic mode


2) Select Apply.

4. Defining Wheel Carrier Attachments

In this section, you define a spherical joint between the wheel carrier and the tie rod. You

then define the mount part that connects the suspension to the steering rack during assembly.

Finally, you create a hooke joint between the tie rod and the steering rack.

To create a spherical joint:

1) Create the spherical joint as follows:

Joint Name: tierod_outer


J Part: ._macpherson.gel_tierod


Active: always

Coordinate Reference: ._macpherson.ground.hpl_tierod_outer

2) Select OK.

To create a mount part for the hooke joint:

1) Create a mount part as follows:

Mount Name: tierod_to_steering

Coordinate Reference: ._macpherson.ground.hpl_tierod_inner

From Minor Role: inherit

2) Select OK.

To create a hooke joint:

1) Create a hooke joint as follows:

Joint Name: tierod_inner

I Part: ._macpherson.gel_tierod

J Part: ._macpherson.mtl_tierod_to_steering

Joint Type: hooke

Active: always

Coordinate Reference: ._macpherson.ground.hpl_tierod_inner

I-Part Axis: ._macpherson.ground.hpl_tierod_outer

J-Part Axis: ._macpherson.ground.hpr_tierod_inner

2) Select Apply.

5. Defining Hub Attachments

You can now define the hub bearing revolute joint between the wheel carrier and the hub.

To define the hub attachment:

1) Create a revolute joint as follows:


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Joint Name: hub_bearing


J Part: ._macpherson.gel_hub

Joint Type: revolute

Active: always

Coordinate Reference: ._macpherson.ground.hpl_wheel_center

Orientation Dependency: Delta orientation from coordinate

Construction Frame: ._macpherson.ground.cfl_hub_bearing

2) Select OK.

6. Defining Suspension Parameters

You create a steering axis using the geometric method for calculating steer axes. When

using the geometric method, ADAMS/Car calculates the steer axis by passing a line through

two non-coincident hardpoints located on the steer axis. To use the geometric method, you

must identify the part(s) and two hardpoints that fix the steer axis.

To create a steer axis:

1) From the Build menu, point to Suspension Parameters, point to Characteristic

Array, and then select Set.


8.3 Creating a Suspension Subsystem

In this section, you create an ADAMS/Car suspension subsystem that is based on the

template you just built. You also modify some hardpoints and translate the subsystem to

ensure that ADAMS/Car correctly positions the subsystem within the assembly.

To create a subsystem:

1) From the File menu, point to New, and then select Subsystem.


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ADAMS/Car displays the following message: The template _macpherson exists in

memory. Do you want to use it?

3) Select Yes.

ADAMS/Car displays the subsystem.

To modify hardpoints:

1) From the Adjust menu, point to Hardpoint, and then select Table.

2) Modify the hardpoint values to match those listed in Table 8.3:


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Table 8.3 Hardpoints To Be Modified

Name: loc_x: loc_y: loc_z:

Hpl_arm_front -200 -400 225

Hpl_arm_rear 200 -390 240

Hpl_tierod_inner 200 -400 300

Hpl_tierod_outer 150 -690 300

3) Select Apply.

4) Select Cancel.

To save the subsystem:

■ From the File menu, select Save.


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9 Creating and Simulating Full Vehicles

This chapter teaches you how to create a full-vehicle assembly, run different types of

analyses, and view the results.

9.1 A Full-Vehicle Assembly

Using ADAMS/Car, you can group separate subsystems and test rigs into an assembly. This

grouping simplifies the opening and saving of subsystems.

In this section, you open an assembly that contains the subsystems for the full vehicle that

you are going to analyze. The assembly we’ve provided for you contains various

subsystems that ADAMS/Car requires to perform steering maneuvers, acceleration

maneuvers, and so on. Full-vehicle assemblies contain the following:

Front/rear suspensions

Steering subsystem

Powertrain

Brake subsystem

Front/rear tires

Rigid chassis

By default, ADAMS/Car includes a vehicle test rig in the assembly.

1. To open an assembly:

1) From the File menu, point to Open, and then select Assembly.

2) Right-click the Assembly Name text box, point to Search, and then select the


3) Double-click MDI_Demo_Vehicle.asy.

4) Select OK.

The Message window appears, informing you that ADAMS/Car is opening the

assembly.

5) When ADAMS/Car is done loading the assembly, select Close.

ADAMS/Car displays the full-vehicle assembly, which should look similar to the one

shown in Figure 21.

2. To create the Full-Vehicle assembly:

1) From the File menu, point to New, and then select Full-Vehicle Assembly.

The New Full-Vehicle Assembly dialog box appears.



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ADAMS/Car displays the full-vehicle assembly, as shown next:

After you create the full-vehicle assembly, you do the following:

To quantify how the vehicle responds to steering inputs, you perform a single

lane-change (open-loop) analysis on the vehicle. A single lane-change analysis

controls the steering subsystem and simulates a simple lane-change maneuver with

the set of parameters you enter when you submit the analysis.

To evaluate the vehicle’s understeer and oversteer characteristics, you run a constant


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radius cornering analysis.

To drive the vehicle through a lane-change course as described in ISO-3888, you run

an ISO lane-change analysis.

After you run each analysis, you animate and plot its results.

9.2 Performing a Single Lane-Change Analysis

Now that you opened a full-vehicle assembly, you can submit a single lane-change analysis.

1. Setting Up the Analysis

You can now specify the inputs for the full-vehicle analysis and perform a single

lanechange maneuver. A single lane-change maneuver indicates that the steering input goes

through a complete sine cycle in the amount of time you specify as the maximum steer

value parameter.

To set up the analysis:

1) From the Simulate menu, point to Full-Vehicle Analysis, point to Open-Loop

Steering Events, and then select Single Lane Change.


Represent the duration and

the resolution of the analysis

3) When the analysis is complete, select Close.

You are now ready to animate and plot the results.


154

2. Animating the Results

In this section, you view the analysis you just ran. ADAMS/Car has already loaded the

analysis results files for you.


2) Select the Play tool .

3) If you want the vehicle to always be in the center of the screen, do the following:

Toggle Fixed Base to Base Part.

Right-click the text box under Base Part, point to Body, and then select Browse.

The Database Navigator appears.

From the list under MDI_Demo_Vehicle, double-click TR_Body, and then

double-click ges_chassis.

4) If you want to see the path the vehicle takes, do the following:

Toggle No Trace to Trace Marker.

Right-click the text box under Trace Marker, point to Marker, and then select

Browse.

The Database Navigator appears.

Double-click TR_BODY.

Double-click ges_chassis.

Double-click cm.

5) To run another animation with either of the options presented in Steps 3 or 4, select the

Play tool.

ADAMS/Car animates the vehicle.

6) To return the assembly to its initial configuration, select the Reset tool .

3. Plotting the Results

In this section, you create two plots that represent the following:

Vehicle lateral acceleration as a function of time

Roll angle of the vehicle as a function of the lateral acceleration

To create a plot of the lateral acceleration with respect to time:

1) From the Review menu, select Postprocessing Window.

2) Verify that Source is set to Requests.

3) From the Simulation list, select fveh_test_sin.

4) From the Filter list, select user defined.

5) From the Request list, select chassis_accelerations. You might have to scroll to see

this option.

6) From the Component list, select lateral.

7) Set the Independent Axis to Time.

8) Select Add Curves.

ADAMS/PostProcessor displays the plot you requested, as shown next:


155

Figure 9.1 Plot of Lateral Acceleration versus Time

Note: Although the y-axis shows NO UNITS, acceleration is expressed in Gs.

9.3 Performing a Step Steer Analysis


1) From the Simulate menu, point to Full-Vehicle Analysis, point to Open-Loop

Steering Events, and then select Step Steer.


Full-Vehicle Assembly: fveh_assy

Output Prefix: tst

End Time: 4

Number of Steps: 100

Initial Velocity: 70 (take the default of km/hr)

Gear Position: 3

Initial Steer Value: 0

Final Steer Value: -45

Step Start Time: 1

Duration of Step: 1

Steering Input: Angle

3) Keep the defaults for Cruise Control (off) and Quasi-Static Straight Line Setup (on).

4) Select Apply, so the dialog box stays open for the analysis you will run in the next

section.

The SDI test rig applies to the assembly the inputs you specified and performs a dynamic

analysis.


156

9.4 Performing a Quasi-Static Steady-State Cornering Analysis

You use an Steady-State Cornering (SSC) analysis to evaluate your full vehicle’s understeer

and oversteer characteristics. The SSC analysis holds the turn radius constant and varies the

vehicle velocity to produce increasing amounts of lateral acceleration. A control subroutine,

CONSUB, controls the analysis and balances all the forces on the body and applies a lateral

acceleration to all model parts.

You can now specify the inputs for the full-vehicle analysis and perform a quasi-static

maneuver.


1) From the Simulate menu, point to Full-Vehicle Analysis, point to Quasi-Static

Maneuvers, and then select Constant Radius Cornering.

2) Run an analysis with the following specifications:

Output Prefix: ssc1

Number of Steps: 30

Final Lateral Accel: .9

Turn Radius: 50

Make sure you set the units pull-down menu for the turn radius to m.

3) Select OK.

ADAMS/Car updates the properties of force entities such as dampers, springs, and bushings,

with the values specified in their property files and sets up the vehicle assembly for the

maneuver.

The number of steps for the output is directly related to the acceleration increment (that is,

acceleration increment = final lateral acceleration / number of steps). ADAMS/Car

performs a static analysis at each lateral acceleration increment. When the vehicle reaches

the specified final lateral acceleration, the maneuver ends automatically.

9.5 Performing a Baseline ISO Lane-Change Analysis

You now perform a baseline ISO lane-change analysis on the new assembly and then plot

and view the results. You then modify the spring and analyze the assembly again.

In an ISO lane-change analysis, the Driving Machine drives your full vehicle through a

lane-change course as described in ISO-3888: Double Lane Change. You specify the gear

position and the desired speed at which to perform the lane change. The analysis stops after

the vehicle travels 250 meters; therefore, the time to complete the return maneuver depends

on the speed that you input.



157

1) From the Simulate menu, point to Full-Vehicle Analysis, point to Course Events,

and then select ISO Lane Change.

2) Set up the analysis with the following characteristics:

Output Prefix: iso1

Initial Velocity: 100

Gear Position: 3

3) Select OK.

9.6 Modifying the Full-Vehicle Assembly

To change the roll angle versus lateral acceleration vehicle characteristic, modify the spring

by creating and assigning a new property file.

After you create a spring property file, assign the

newly created property file to the front and rear springs.

1. To create a new spring property file:

1) From the Tools menu, select Curve Manager.

2) From the File menu, select New.

3) Verify that Type is set to spring.

4) Select OK.

ADAMS/Car generates a plot of the spring displacement

versus force characteristic in the plot window of the Curve

Manager.

5) In the Slope text box, enter 225.

6) Make sure the extension/compressions limits are set to

-100, 100.

7) Select Apply.

ADAMS/Car modifies the spring characteristic.

8) In the Free Length text box, enter 300.

9) Select Apply.

10) From the File menu, select Save.

11) In the File text box, enter my_spring.

12) Select OK.

13) Close the Curve Manager.

ADAMS/Car returns to the main window.

2. To modify the springs:

1) In the model, right-click the front spring, ns[lr]_ride_spring, and then select Modify.

The Modify Spring dialog box loads the spring parameters in the text boxes.

2) Right-click the Property File text box and, from your default writable database, select


158

my_spring.spr.

3) Replace Installed Length with Preload.

4) Enter a Preload of 5500.

5) Select Apply.

ADAMS/Car assigns the new property file to the spring.

6) Repeat Steps 1 through 4 for the rear springs.

7) Select OK.


159

APPENDIX A: ADAMS/View keyboard shortcuts

This appendix shows the keyboard shortcuts for ADAMS/View. Keyboard shortcuts are key

combinations that access commands quickly. When you enter a keyboard shortcut, the focus

must be in the main window except when entering a keyboard shortcut that works in dialog

boxes.

File Operations

Table 1. File Operation Shortcuts

To: Select:

Create a new modeling database Ctrl +n

Open an existing modeling database Ctrl + o

Save the current modeling database Ctrl + s

Print Ctrl + p

Read command file F2

Exit Ctrl + q

Edit Operations

Table 2. Edit Operation Shortcuts

To: Select:

Undo the last operation Ctrl + z

Redo the last undone operation Ctrl + Shift + z

Copy objects Ctrl + c

Paste text in text boxes in dialog boxes and as comments Ctrl + v

Cut text from text boxes in dialog boxes Ctrl + x

Quickly clear text from text boxes Left-click at the

start of the text box,

and then press

Ctrl+k or Ctrl-K

Delete selected object del

Modify object Ctrl + e

Escape operation Esc

Appendix A: ADAMS/View keyboard shortcuts

160

Display Operations

Table 3. Display Operation Shortcuts

To display: Select:

Command window F3

Coordinate window F4

Menu Builder F5

Dialog Box Builder F6

Working grid g

Plotting window (ADAMS/PostProcessor) F8

Help window F1

Viewing Operations

Table 4. Viewing Operation Shortcuts

To: Select:

Rotate view in the XY directions r

Rotate view in the Z direction s (lowercase)

Translate view t

Change perspective depth d

Dynamically zoom view z

Use dynamic increment Shift

Define a zoom area w

Center view c

Orient view to object e

Fit view f

Fit view – no ground Ctrl + F

Orient view to front F

Orient view to right R

Orient view to top T

Orient view to isometric I

Toggle render mode between wireframe and shaded S (uppercase)

Toggle screen icons on and off v


161

Drawing Operations

Table 5. Drawing Operation Shortcuts

To: Select and hold:

Turn off snapping to geometry Ctrl

Turn off highlighting of geometry during selection Ctrl

Appendix B: ADAMS/Car keyboard shortcuts

162

APPENDIX B: ADAMS/Car keyboard shortcuts

This section shows the keyboard shortcuts for ADAMS/Car. Keyboard shortcuts are key

combinations that access commands quickly. When you enter a keyboard shortcut, the focus

must be in the main window, except when entering a keyboard shortcut that works in dialog

boxes.

File Operations

Table 1. File Operation Shortcuts

To: Select:

Create a new template (in Template Builder) Ctrl +n

Open an existing assembly (in Standard Interface) or

template (in Template Builder)

Ctrl + o

Open a subsystem (in Standard Interface) Ctrl + u

Save the current template (in Template Builder) Ctrl + s

Print Ctrl + p

Select file F2

Exit Ctrl + q

Edit Operations

Table 2. Edit Operation Shortcuts

To: Select:

Undo the last operation Ctrl + z

Redo the last undone operation Ctrl + Shift + z

Copy text in text boxes in dialog boxes Ctrl + c

Paste text in text boxes in dialog boxes and as comments Ctrl + v

Cut text from text boxes in dialog boxes Ctrl + x

Delete selected object Ctrl + x

Modify selected object; if no object is selected,

ADAMS/Car displays the Database Navigator

Ctrl + e

Escape operation Esc


163

Display Operations

Table 3. Display Operation Shortcuts

To display: Select:

Command window F3

Coordinate window F4

Working grid g

Plotting window (in Standard Interface) F8

Help window F1

Standard Interface/Template Builder F9

Viewing Operations

Table 4. Viewing Operation Shortcuts

To: Select:

Rotate view in the XY directions r

Rotate view in the Z direction s (lowercase)

Translate view t

Change perspective depth d

Dynamically zoom view z

Use dynamic increment; use this shortcut in conjunction with

the above five shortcuts to increment the view. For example,

press r to rotate, and then press Shift to rotate incrementally.

Shift

Define a zoom area w

Center view c

Orient view to object e

Fit view f

Orient view to front F

Orient view to right R

Orient view to left L

Orient view to top T

Orient view to isometric I

Orient view to plan P

Toggle render mode between wireframe and shaded S (uppercase)

Toggle screen icons on and off v

REFERENCES

164

REFERENCES

1 Mechanical Dynamics Inc. Road Map to ADAMS/View Documentation

2 Mechanical Dynamics Inc. Road Map to ADAMS/Car Documentation

3 Mechanical Dynamics Inc. Getting Started Using ADAMS/Controls

4 Mechanical Dynamics Inc. Using ADAMS/Driver

5 Mechanical Dynamics Inc. Road Map to ADAMS/FLEX Documentation

6 Mechanical Dynamics Inc. Using ADAMS/PostProcessor

7 Mechanical Dynamics Inc. Road Map to ADAMS/Solver Documentation

8 Mechanical Dynamics Inc. Road Map to ADAMS/Tire Documentation

9 王国强，张进平，马若丁. 虚拟样机技术及其在 ADAMS 上的实践. 西安: 西北

工业大学出版社, 2002

10 李军, 邢俊文, 谭文洁. ADAMS 实例教程. 北京: 北京理工大学出版社, 2002

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