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Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
3D Dynamic Analysis of machine vibrations on foundation and structure
By Angel Francisco Martinez
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
ContentsPart 1. Introduction
Part 2. Concepts of Dynamic Loads
Part 3. 3D Raft Foundation Model
Part 4. 3D Metallic Plant Model
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
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Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
midas FX+
midas NFX
Mecánica
General Pre & Post Processor
for Finite Element Analysis
Integrated Design System
for Building and General Structures
midas Gen
Edificios y Estructuras Generales
2D / 3D Geotechnical and Tunnel
analysis System
midas GTS NX
SoilWorks
Geotecniay Túneles
midas Civil
midas FEA
Puentes
Integrated Solution System
for Bridge and Civil Structures
Advanced Nonlinear and Detail
Analysis System
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Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
ContentsPart 1. Introduction
Part 2. Concepts of Dynamic Loads
Part 3. 3D Raft Foundation Model
Part 4. 3D Metallic Plant Model
GTS NX
Dynamic loads are used to apply various changing load conditions for linear/nonlinear time history
analysis. The total load vector in time history analysis is defined as the following function of time, . t
Here, is the j th load scale and it is generally defined as a tabular data form for time, or by
inputting coefficients for a particular function
Dynamic load
GTS NX
The nonlinearity of the system often results from material nonlinearity or geometric nonlinearity. In addition, there are cases where nonlinear analysis is needed for systems with load nonlinearity. For example, when the load direction changes with the structural displacement or when the load size is dependent on the structural behavior. GTS NXL can reflect the effects of follower loads, where the load direction changes with the structural displacement when performing geometric nonlinear analysis.
Nonlinearity of Loads
When the nodal force direction is determined by the relative position of two different points, its size and
direction are as follows:
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
ContentsPart 1. Introduction
Part 2. Concepts of Dynamic Loads
Part 3. 3D Raft Foundation Model
Part 4. 3D Metallic Plant Model
GTS NX
11
Geometry Import
Define Materials
Mesh generation
Boundary Conditions
Dynamic Load Conditions
Eigenvalue Analysis
STEP 01
STEP 02
STEP 03
STEP 04
STEP 05
STEP 06
TH Analysis CaseSTEP 07
STEP 08 Perform analysis and check result
Overview
GTS NX
12
00 Material for Soil
Name Weathered Soil Concrete
Material Isotropic Isotropic
Model Type Mohr-Coulomb Elastic
General
Elastic Modulus (E) (ton/m^2) 3,000 2200000
Poisson’s Ratio(v) 0.35 .3
Unit Weight(r) (ton/m^3) 1.9 2.5
K0 1 1
Porous
Unit Weight(Saturated) (ton/m^3) 2 2.5
Non-Linear
Friction Angle 30
Cohesion (ton/m^2) 1.8
GTS NX
13
00 Property for Soil
Name Weathered Soil Concrete
Property 3D 3D
Model Type Solid Solid
Material Weathered Soil Concrete
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
Modeling Procedure
GTS NX
Procedure
1-15
01 Create New Project
11
Main Menu > New
Analysis Setting > Model
Type > 3D
Set units to tonf / m / sec
2
2
GTS NX
Procedure
1-16
02
1
1
Main Menu > Import > CAD File
Select Vibration Load 3d geometry >
Open
Select OK
2
3
3
Geometry works (Create or Import from AutoCAD)
2
GTS NX
Procedure
1-17
03 Define Material / Property for Soil & Structures
1
Mesh > Prop. > Property >
Create > 3D
Define 3D n properties for
both materials
•Define Materials and Properties
Material > Create > Isotropic
Define the 2 materials based on
properties from table in previous
slide
1
2
2
2
1
GTS NX
Procedure
1-18
04 Generate Mesh (3D Element)
1 Mesh > Generate > 3D > Auto Solid
Select Edge(s) > Select 2 soilds
highlighted in figure.
Input element Size : 0.5
(0.5m between two nodes)
Select Property : foundation 3d
Input Mesh Set Name : foundation
Click APPLY
2
2
3
4
5 3
4
5
6
6
1
1
GTS NX
Procedure
1-19
04 Generate Mesh (3D Element)
1 Mesh > Generate > 3D > Auto - Solid
Select Edge(s) > Select 2 solids
highlighted in figure.
Input element Size : 2
(1m between two nodes)
Select Property : weathered soil
Input Mesh Set Name : weathered soil
Click APPLY
2
2
3
4
5
3
4
5
6
6
1
1
GTS NX
Procedure
1-20
05 Define Dynamic Boundary Conditions
Mesh > Element > Other > Ground Surface
Springs
Select the 2 ground mesh sets
Press OK
1
2
3
3
1
2
1
2
GTS NX
Procedure
1-21
06 Analysis Case
1
Create EigenValue Analysis Cases
1. Analysis > Analysisi Case >
General > Eigenvalue
2. Activate All Sets
3. Analysis Control > 30 Modes
4. Press OK > OK
2
31
2
3
3
4
4
4
GTS NX
Procedure
1-22
07 Perform Analysis and Check Results
1 Analysis > Analysis > Perform
Select OK
1
2
2
GTS NX
Procedure
1-23
08 Post Processing (Results)
* After analysis, model view will be
converted to Post-Mode automatically,
can back to Pre-Mode to change model
information.
1 1
Results can be Viewed in table
format.
Find the 2 highest mass
participation modes in T3 (vertical direction)
and write down their corresponding periods.
MODE 3: 1.108514 sec
MODE 4: 1.294852 sec
3
2
GTS NX
Procedure
1-24
09 Define Dynamic Boundary Conditions
Mesh > Element > Other > Dampers
Select the ground mesh set
Select Damping Constant / Area option
Name set as : Dampers
Press OK
1
2
3
4
1
2
1
2
3
4
5
5
GTS NX
Procedure
1-25
10 Define Dynamic Load
• Create the cyclic load condition for
the time history analysis case.
Work Tree > Analysis > Time Forcing
Function > Add
1
Select Add Time Function
Open Excell file and copy the coulmns as
shown in the image.
Paste into the Time History Load Function
chart
Select Force under Time Function Type
Press OK > Close
3
2
3
2
1
4
4
6
6
5
5
6
GTS NX
Procedure
1-26
11 Apply Dynamic Load
• Apply the cyclic load to the
foundation surface.
Dynamic Analysis > Dynamic Load
1
Select the nodes on the top of the foundation
Assign Tz: -1
Select ‘LOAD’ for Time Function
Press OK
3
2
1
4
5
2
3
4
5
2
GTS NX
Procedure
1-27
12 Analysis Case (Linear Time History)
1
Create Linear Time History Analysis
Case
Analysis > General > Linear Time
History Direct
Activate all sets except Ground
Surface Springs
Define Time Step
Name: time
Time Duration: 0.5 sec
Time Increment:: 0.005 sec
Intermediate Output:: 1
Press Add > OK
Analysis Control > Dynamic >
Damping Method
-Select > Calculate from Modal
Damping > Period
-Type in the 2 periods from
Eigenvalue results
-Damping Ratio : 0.05
Press OK>OK
2
3
1
2
3
4
4
4
4
5
5
6
3
GTS NX
Procedure
1-28
13 Perform Analysis and Check Results
1 Analysis > Analysis > Perform
Select Linear Time History
Select OK
1
3
2
3
2
GTS NX
Procedure
1-29
1 Inspect results to dynamic load
Incr = 1 > Displacements > Total
Translation. Deactivate 1 ground and 1
foundation mesh set to see plane cut.
Switch units to mm
Navigate the results over time steps by
clicking on the bar under the model
and pressing the right button on key
board to go forward
2
14 Post Processing (Post mode)
1
2
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
ContentsPart 1. Introduction
Part 2. Concepts of Dynamic Loads
Part 3. 3D Raft Foundation Model
Part 4. 3D Metallic Plant Model
GTS NX
31
3D Modeling
• Modeling in midas GTS NX
- Import Structure from Gen
- Create Solid Ground
- Assing Size Control to base to match nodes
GTS NX
Mesh Generation• Generate Mesh and Create Elements
- Ground material and structural properties
- Generate mesh for ground, and structure
- Generate Ground Surface Springs
GTS NX
Eigenvalue• Run Eigen Value analysis
- Find the modes with highest mass
participation in z direction (T3)
- Write down the 2 periods for mode numbers
GTS NX
34
Load & Dampers
• Load Conditions
- Dynamic Cycle Load
• Boundary Conditions
-Dampers
GTS NX
35
Non linear time history• Set parameters
-Time Steps
- Define periods for mass and stiffness proportional
damping
GTS NX
36
Post-Processing• Report Ready Results
- Extract Results for time steps
- Settlement Profile over time
- Graph Axial forces on column
- Stresses on soil
Integrated Solver Optimized for the next generation 64-bit platform
Finite Element Solutions for Geotechnical Engineering
Q&Alamidas@midasuser.com