Estimated Time for Completion: 30 minutesExperience Level: Lower

MSC.Marc 2005r2MSC.Patran 2005r2

Spring Design using Parametric Modeling

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Topics Covered

• Using Parametric Modeling tool

• Modifying Session file

• Playing Session file

• Creating Database file for input values for parameters

• Creating 3D solid elements

• Applying Displacement and Load boundary conditions

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Problem Description

• This example illustrate how design modification process can be accelerated by using Parametric Modeling tool and modifying the Session file. After developing the first model of a Helical Spring, design modification is done by changing the values of design parameters.

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Summary of Model

Fixed boundary condition

Load applied

r2

r1

Design parameters

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Create DB file and Define Design Parameters

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a. Click File menu / Select New

b. In File Name enter spring.db

c. Click OK

d. In Approximate Maximum Model Dimension, enter 0.1

e. Select Analysis Code to be MSC. Marc

f. Click OK

g. Click Tools menu > Pre Release > Parametric Modeling…

h. Select Action to be Create

i. Select Object to be Variables

j. In Variable Name, enter r1

k. In Current Value, enter 20e-3

l. Click Apply.

m. In Variable Name, enter r2

n. In Current Value, enter 3e-2

o. Click Apply

p. Select Action to be Create

q. Select Object to be Macros

r. In Macro Name, enter GEL

s. In Macro Definition, enter ~r2~*2

t. Click Apply

u. Click Done

You can use Tab button here to move the cursor.

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Modeling

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a. Click Geometry icon

b. Select Action to be Create

c. Select Object to be Curve

d. Select Method to be XYZ

e. In Vector Coordinates List, enter <0,0.005,0>

f. Click Apply

g. Select Action to be Transform

h. Select Object to be Curve

i. Select Method to be Translate

j. In Direction Vector, enter <0,0.005,0>

k. In Repeat Count, enter 19

l. In Curve List, enter Curve 1 or select the one just made using the mouse left button.

m. Click Apply if Auto Execute is not selected

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Modeling

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a. Select Action to be Create

b. Select Object to be Curve

c. Select Method to be 2D ArcAngles

d. In Radius, enter `r1`

e. In End Angle, enter 90

f. In Construction Plane List, enter Coord 0.2 or

g. Select the coordinates icon with number 2, and select the default coordinates.

h. Click Apply

i. Select Action to be Transform

j. Select Object to be Curve

k. Select Method to be Rotate

l. In Axis, enter Coord 0.2

m. In Rotation Angle, enter 90

n. In Repeat Count, enter 3

o. In Curve List, enter Curve 21 or select the curve just made.

p. Click Apply if Auto Execute is not selected

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Use Grave instead Apostrophe.

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Modelinga. Select Action to be Transform

b. Select Object to be Curve

c. Select Method to be Vsum

d. In Curve 1 List, enter Curve 1:20

e. In Curve 2 List, enter Curve 21:24 21:24 21:24 21:24 21:24

f. Click Apply if Auto Execute is not selected

g. Select Action to be Create

h. Select Object to be Curve

i. Select Method to be 2D Normal

j. In Curve Length, enter `r2`

k. In Construction Plane List, enter Coord 0.2 0.3

l. In Point List, enter Point 22

m. In Curve List, enter Curve 25

n. Click Apply if Auto Execute is not selected

o. Select Action to be Create

p. Select Object to be Coord

q. Select Method to be 3Point

r. In Origin, enter Point 22

s. In Point on Axis 3, enter Point 47

t. In Point on Plane 1-3, enter Point 46

u. Click Apply if Auto Execute is not selected

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Modeling

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a. Select Action to be Create

b. Select Object to be Curve

c. Select Method to be Revolve

d. In Axis, enter Coord 1.2

e. In Total Angle, enter 90

f. In Point List, enter Point 47

g. Click Apply if Auto Execute is not selected

h. Select Action to be Transform

i. Select Object to be Curve

j. Select Method to be Rotate

k. In Axis, enter Coord 1.2

l. In Rotation Angle, enter 90

m. In Repeat Count, enter 3

n. In Curve List, enter Curve 47

o. Click Apply if Auto Execute is not selected

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Modeling

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a. Select Action to be Create

b. Select Object to be Surface

c. Select Method to be Edge

d. In Surface Edge 1 List,enter Curve 47

e. In Surface Edge 2 List,enter Curve 48

f. In Surface Edge 3 List,enter Curve 49

g. In Surface Edge 4 List,enter Curve 50

h. Click Apply if Auto Execute is not selected

i. Select Action to be Create

j. Select Object to be Solid

k. Select Method to be Glide

l. Select Normal Project Glide radio button

m. In Director Curve List, enter Curve 25:44

n. In Base Surface List, enter Surface 1

o. Click Apply if Auto Execute is not selected

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Meshing

a. Click Element icon

b. Select Action to be Create

c. Select Object to be Mesh

d. Select Method to be Solid

e. Click TetMesh Parameter

f. In Global Edge Length*, enter 0.5

g. Click OK

h. In Input List, enter Solid 1:20

i. Off the Autmatic Calculation Check box

j. In Value, enter `GEL()`

k. Click Apply

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Applying Load and Boundary Condition

a. Click Loads/BCs icon

b. Select Action to be Create

c. Select Object to be Displacement

d. Select Type to be Nodal

e. In New Set Name, enter fixed_end

f. Click Input Data…

g. In Translations, enter <0,0,0>

h. Click OK

i. Click Select Application Region…

j. In Select Geometry Entities, enter Solid 1.5

k. Click Add

l. Click OK

m. Click Apply

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Applying Load and Boundary Condition

a. Click Loads/BCs icon

b. Select Action to be Create

c. Select Object to be Force

d. Select Type to be Nodal

e. In New Set Name, enter forceup

f. Click Input Data…

g. In Translations, enter <0,1,0>

h. Click OK

i. Click Select Application Region…

j. In Select Geometry Entities, enter Solid 20.6

k. Click Add

l. Click OK

m. Click Apply

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Creating Material Properties

a. Click Materials icon

b. Select Action to be Create

c. Select Object to be Isotropic

d. Select Method to be Manual Input

e. In Material Name, enter aluminum

f. Click Input Data…

g. In Elastic Modulus, enter 7e10

h. In Posson Ratio, enter 0.33

i. Click OK

j. Click Apply

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Creating Element Properties

a. Click Properties icon

b. Select Action to be Create

c. Select Object to be 3D

d. Select Type to be Solid

e. In Property Set Name, enter spring

f. Click Input Properties…

g. In Material Name, enter m:aluminum

h. Click OK

i. In Select Members, enter Solid 1:20

j. Click Add

k. Click Apply

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Running Analysis and Reading Results

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a. Click Analysis icon

b. Select Action to be Analyze

c. Select Object to be Entire Model

d. Select Method to be Full Run

e. In Job Name, enter spring_ext

f. Click Apply

g. Select Action to be Read Results

h. Select Object to be Result Entities

i. Select Method to be Attach

j. In Job Name, enter spring_ext

k. Click Apply

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Creating Database File and Modifying Session File

a. Click the mouse right button

b. In the popup menu, New > Text Document.

c. Create new file named, my_config.dat

d. Edit and Add following two lines to the file.r1=30e-3r2=3-e-3

e. Save and Exit the file

a. Edit the session file, spring.ses, which has been made automatically by MSC.Patran.

b. Add the following line at the first line.parametric_modeling_util.define_user_config_file("my_config.dat")

c. Save and Exit the file

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Running the Session filea. Click File menu

b. Select Session > Play…

c. In File Name enter spring.ses or click the file

d. Click Apply

Note: Session file and the Parameter database file must be in the same folder.

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Expected Results (Displacement)

Max displacement = 1.49e-2

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Expected Results (Displacement)

Max displacement = 1.41e-3