ANSYS Mechanical APDL Advanced Analysis Guide

414 Pages·2013·7.43 MB·English

ANSYS Mechanical APDL Advanced Analysis
Guide
ANSYS, Inc. Release 15.0
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Table of Contents
1. Probabilistic Design................................................................................................................................ 1
1.1. Understanding Probabilistic Design.................................................................................................. 1
1.1.1.Traditional (Deterministic) vs. Probabilistic Design Analysis Methods......................................... 2
1.1.2. Reliability and Quality Issues.................................................................................................... 3
1.2. Probabilistic Design Terminology...................................................................................................... 3
1.3. Using Probabilistic Design................................................................................................................. 8
1.3.1. Create the Analysis File............................................................................................................. 9
1.3.1.1. Example Problem Description........................................................................................ 10
1.3.1.2. Build the Model Parametrically....................................................................................... 10
1.3.1.3. Obtain the Solution....................................................................................................... 11
1.3.1.4. Retrieve Results and Assign as Output Parameters.......................................................... 11
1.3.1.5. Prepare the Analysis File................................................................................................ 12
1.3.2. Establish Parameters for Probabilistic Design Analysis............................................................. 12
1.3.3. Enter the PDS and Specify the Analysis File............................................................................. 13
1.3.4. Declare Random Input Variables............................................................................................. 14
1.3.5.Visualize Random Input Variables........................................................................................... 20
1.3.6. Specify Correlations Between Random Variables..................................................................... 20
1.3.7. Specify Random Output Parameters....................................................................................... 23
1.3.8. Select a Probabilistic Design Method...................................................................................... 24
1.3.8.1. Probabilistic Method Determination Wizard................................................................... 24
1.3.9. Execute Probabilistic Analysis Simulation Loops...................................................................... 25
1.3.9.1. Probabilistic Design Looping......................................................................................... 26
1.3.9.2. Serial Analysis Runs....................................................................................................... 27
1.3.9.3. PDS Parallel Analysis Runs.............................................................................................. 27
1.3.9.3.1. Machine Configurations........................................................................................ 29
1.3.9.3.1.1. Choosing Slave Machines............................................................................. 29
1.3.9.3.1.2. Using the Remote Shell Option..................................................................... 29
1.3.9.3.1.3. Using the Connection Port Option................................................................ 31
1.3.9.3.1.4. Configuring the Master Machine................................................................... 33
1.3.9.3.1.5. Host setup using port option........................................................................ 35
1.3.9.3.1.6. Host and Product selection for a particular analysis....................................... 35
1.3.9.3.2. Files Needed for Parallel Run................................................................................. 36
1.3.9.3.3. Controlling Server Processes................................................................................. 37
1.3.9.3.4. Initiate Parallel Run............................................................................................... 38
1.3.10. Fit and Use Response Surfaces.............................................................................................. 38
1.3.10.1. About Response Surface Sets....................................................................................... 39
1.3.10.2. Fitting a Response Surface........................................................................................... 39
1.3.10.3. Plotting a Response Surface......................................................................................... 40
1.3.10.4. Printing a Response Surface......................................................................................... 40
1.3.10.5. Generating Monte Carlo Simulation Samples on the Response Surfaces........................ 41
1.3.11. Review Results Data............................................................................................................. 41
1.3.11.1.Viewing Statistics......................................................................................................... 42
1.3.11.2.Viewing Trends............................................................................................................ 43
1.3.11.3. Creating Reports.......................................................................................................... 44
1.4. Guidelines for Selecting Probabilistic Design Variables..................................................................... 44
1.4.1. Choosing and Defining Random Input Variables..................................................................... 44
1.4.1.1. Random Input Variables for Monte Carlo Simulations..................................................... 45
1.4.1.2. Random Input Variables for Response Surface Analyses.................................................. 45
1.4.1.3. Choosing a Distribution for a Random Variable............................................................... 45
1.4.1.3.1. Measured Data ..................................................................................................... 45
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1.4.1.3.2. Mean Values, Standard Deviation, Exceedence Values............................................. 46
1.4.1.3.3. No Data................................................................................................................ 46
1.4.1.4. Distribution Functions................................................................................................... 49
1.4.2. Choosing Random Output Parameters.................................................................................... 50
1.5. Probabilistic Design Techniques...................................................................................................... 51
1.5.1. Monte Carlo Simulations........................................................................................................ 51
1.5.1.1. Direct Sampling............................................................................................................. 51
1.5.1.2. Latin Hypercube Sampling............................................................................................. 52
1.5.1.3. User-Defined Sampling.................................................................................................. 53
1.5.2. Response Surface Analysis Methods....................................................................................... 55
1.5.2.1. Central Composite Design Sampling.............................................................................. 56
1.5.2.2. Box-Behnken Matrix Sampling....................................................................................... 58
1.5.2.3. User-Defined Sampling.................................................................................................. 58
1.6. Postprocessing Probabilistic Analysis Results................................................................................... 59
1.6.1. Statistical Postprocessing....................................................................................................... 59
1.6.1.1. Sample History.............................................................................................................. 59
1.6.1.2. Histogram..................................................................................................................... 60
1.6.1.3. Cumulative Distribution Function.................................................................................. 60
1.6.1.4. Print Probabilities.......................................................................................................... 62
1.6.1.5. Print Inverse Probabilities............................................................................................... 62
1.6.2.Trend Postprocessing............................................................................................................. 62
1.6.2.1. Sensitivities................................................................................................................... 62
1.6.2.2. Scatter Plots.................................................................................................................. 65
1.6.2.3. Correlation Matrix.......................................................................................................... 67
1.6.3. Generating an HTML Report................................................................................................... 67
1.7. Multiple Probabilistic Design Executions......................................................................................... 67
1.7.1. Saving the Probabilistic Design Database................................................................................ 68
1.7.2. Restarting a Probabilistic Design Analysis............................................................................... 68
1.7.3. Clearing the Probabilistic Design Database............................................................................. 69
1.8. Example Probabilistic Design Analysis............................................................................................. 69
1.8.1. Problem Description.............................................................................................................. 69
1.8.2. Problem Specifications........................................................................................................... 69
1.8.2.1. Problem Sketch............................................................................................................. 70
1.8.3. Using a Batch File for the Analysis........................................................................................... 70
1.8.4. Using the GUI for the PDS Analysis.......................................................................................... 72
2.Variational Technology......................................................................................................................... 75
2.1. Harmonic Sweep Using VT Accelerator............................................................................................ 75
2.1.1. Structural Elements Supporting Frequency-Dependent Properties.......................................... 76
2.1.2. Harmonic Sweep for Structural Analysis with Frequency-Dependent Material Properties......... 76
2.1.2.1. Beam Example............................................................................................................... 77
3. Adaptive Meshing................................................................................................................................. 79
3.1. Prerequisites for Adaptive Meshing................................................................................................. 79
3.2. Employing Adaptive Meshing......................................................................................................... 79
3.3. Modifying the Adaptive Meshing Process........................................................................................ 80
3.3.1. Selective Adaptivity ............................................................................................................... 80
3.3.2. Customizing the ADAPT Macro with User Subroutines ............................................................ 81
3.3.2.1. Creating a Custom Meshing Subroutine (ADAPTMSH.MAC)............................................ 81
3.3.2.2. Creating a Custom Subroutine for Boundary Conditions (ADAPTBC.MAC)....................... 82
3.3.2.3. Creating a Custom Solution Subroutine (ADAPTSOL.MAC).............................................. 82
3.3.2.4. Some Further Comments on Custom Subroutines.......................................................... 82
3.3.3. Customizing the ADAPT Macro (UADAPT.MAC)....................................................................... 83
3.4. Adaptive Meshing Hints and Comments.......................................................................................... 83
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3.5.Where to Find Examples.................................................................................................................. 84
4. Rezoning ............................................................................................................................................... 87
4.1. Benefits and Limitations of Rezoning............................................................................................... 87
4.1.1. Rezoning Limitations.............................................................................................................. 89
4.2. Rezoning Requirements.................................................................................................................. 90
4.3. Understanding the Rezoning Process.............................................................................................. 92
4.3.1. Overview of the Rezoning Process Flow.................................................................................. 93
4.3.2. Key Commands Used in Rezoning .......................................................................................... 96
4.4. Step 1: Determine the Substep to Initiate Rezoning.......................................................................... 97
4.5. Step 2. Initiate Rezoning.................................................................................................................. 98
4.6. Step 3: Select a Region to Remesh................................................................................................... 98
4.7. Step 4: Perform the Remeshing Operation....................................................................................... 99
4.7.1. Choosing a Remeshing Method.............................................................................................. 99
4.7.1.1. Remeshing Using a Program-Generated New Mesh (2-D).............................................. 100
4.7.1.1.1. Creating an Area to Remesh................................................................................ 100
4.7.1.1.2. Using Nodes From the Old Mesh......................................................................... 100
4.7.1.1.3. Hints for Remeshing Multiple Regions ................................................................ 101
4.7.1.1.4. Generating a New Mesh ..................................................................................... 101
4.7.1.2. Remeshing Using a Generic New Mesh (2-D and 3-D)................................................... 101
4.7.1.2.1. Using the REMESH Command with a Generic New Mesh...................................... 102
4.7.1.2.2. Requirements for the Generic New Mesh............................................................. 102
4.7.1.2.3. Using the REGE and KEEP Remeshing Options..................................................... 103
4.7.1.3. Remeshing Using Manual Mesh Splitting (2-D and 3-D)................................................ 105
4.7.1.3.1. Understanding Mesh Splitting............................................................................. 105
4.7.1.3.2. Geometry Details for Mesh Splitting ................................................................... 105
4.7.1.3.3. Using the REMESH Command for Mesh Splitting.................................................. 108
4.7.1.3.4. Mesh-Transition Options for 2-D Mesh Splitting................................................... 108
4.7.1.3.5. Mesh-Transition Options for 3-D Mesh Splitting................................................... 110
4.7.1.3.6. Improving the Local Topology of Tetrahedral Meshes via Edge and Face Swap-
ping ................................................................................................................................. 112
4.7.1.3.7. Improving Tetrahedral Element Quality via Mesh Morphing ................................. 113
4.7.2. Mesh Control ....................................................................................................................... 114
4.7.3. Remeshing Multiple Regions at the Same Substep................................................................ 115
4.8. Step 5:Verify Applied Contact Boundaries, Surface-Effect Elements, Loads, and Boundary Condi-
tions................................................................................................................................................... 116
4.8.1. Contact Boundaries.............................................................................................................. 116
4.8.2. Surface-Effect Elements ....................................................................................................... 116
4.8.3. Pressure and Contiguous Displacements............................................................................... 116
4.8.4. Forces and Isolated Applied Displacements........................................................................... 117
4.8.5. Nodal Temperatures............................................................................................................. 117
4.8.6. Other Boundary Conditions and Loads................................................................................. 117
4.9. Step 6: Automatically Map Variables and Balance Residuals............................................................ 118
4.9.1. Mapping Solution Variables.................................................................................................. 118
4.9.2. Balancing Residual Forces..................................................................................................... 118
4.9.3. Interpreting Mapped Results................................................................................................ 119
4.9.4. Handling Convergence Difficulties........................................................................................ 120
4.10. Step 7: Perform a Multiframe Restart............................................................................................ 120
4.11. Repeating the Rezoning Process if Necessary............................................................................... 120
4.11.1. File Structures for Repeated Rezonings............................................................................... 121
4.12. Postprocessing Rezoning Results................................................................................................. 121
4.12.1.The Database Postprocessor............................................................................................... 121
4.12.1.1. Listing the Rezoning Results File Summary................................................................. 122
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4.12.1.2. Animating the Rezoning Results................................................................................. 122
4.12.1.3. Using the Results Viewer for Rezoning........................................................................ 122
4.12.2.The Time-History Postprocessor.......................................................................................... 123
4.13. Rezoning Restrictions.................................................................................................................. 123
4.14. Rezoning Examples..................................................................................................................... 124
4.14.1. Example: Rezoning Using a Program-Generated New Mesh................................................. 124
4.14.1.1. Initial Input for the Analysis........................................................................................ 125
4.14.1.2. Rezoning Input for the Analysis.................................................................................. 127
4.14.2. Example: Rezoning Using a Generic New Mesh.................................................................... 127
4.14.2.1. Initial Input for the Analysis........................................................................................ 128
4.14.2.2. Exporting the Distorted Mesh as a CDB File................................................................ 130
4.14.2.3. Importing the File into ANSYS ICEM CFD and Generating a New Mesh......................... 131
4.14.2.4. Rezoning Using the New CDB Mesh........................................................................... 132
5. Mesh Nonlinear Adaptivity................................................................................................................. 135
5.1. Mesh Nonlinear Adaptivity Benefits, Limitations and Requirements................................................ 135
5.1.1. Rubber Seal Simulation........................................................................................................ 136
5.1.2. Crack Simulation.................................................................................................................. 139
5.2. Understanding the Mesh Nonlinear Adaptivity Process.................................................................. 142
5.2.1. Checking Nonlinear Adaptivity Criteria................................................................................. 143
5.2.1.1. Defining Element Components.................................................................................... 143
5.2.1.2. Defining Nonlinear Adaptivity Criteria.......................................................................... 144
5.2.1.3. Defining Criteria-Checking Frequency.......................................................................... 144
5.3. Mesh Nonlinear Adaptivity Criteria................................................................................................ 144
5.3.1. Energy-Based....................................................................................................................... 144
5.3.2. Position-Based ..................................................................................................................... 144
5.3.3. Contact-Based...................................................................................................................... 145
5.3.4. Frequency of Criteria Checking............................................................................................. 145
5.4. How a New Mesh Is Generated...................................................................................................... 146
5.5. Convergence at Substeps with the New Mesh................................................................................ 149
5.6. Controlling Mesh Nonlinear Adaptivity.......................................................................................... 150
5.7. Postprocessing Mesh Nonlinear Adaptivity Results........................................................................ 150
5.8. Mesh Nonlinear Adaptivity Examples............................................................................................. 150
5.8.1. Example: Rubber Seal Simulation.......................................................................................... 151
5.8.2. Example: Crack Simulation.................................................................................................... 153
6. 2-D to 3-D Analysis.............................................................................................................................. 155
6.1. Benefits of 2-D to 3-D Analysis....................................................................................................... 155
6.2. Requirements for a 2-D to 3-D Analysis ......................................................................................... 155
6.3. Overview of the 2-D to 3-D Analysis Process.................................................................................. 157
6.3.1. Overview of the 2-D to 3-D Analysis Process Flow.................................................................. 157
6.3.2. Key Commands Used in 2-D to 3-D Analysis .......................................................................... 158
6.4. Performing a 2-D to 3-D Analysis................................................................................................... 159
6.4.1. Step 1: Determine the Substep to Initiate.............................................................................. 159
6.4.2. Step 2: Initiate the 2-D to 3-D Analysis................................................................................... 160
6.4.3. Step 3: Extrude the 2-D Mesh to the New 3-D Mesh .............................................................. 160
6.4.4. Step 4: Map Solution Variables from 2-D to 3-D Mesh............................................................. 161
6.4.5. Step 5: Perform an Initial-State-Based 3-D Analysis................................................................ 161
6.5. 2-D to 3-D Analysis Restrictions..................................................................................................... 161
7. Cyclic Symmetry Analysis.................................................................................................................... 163
7.1. Understanding Cyclic Symmetry Analysis...................................................................................... 163
7.1.1. How the Program Automates a Cyclic Symmetry Analysis...................................................... 163
7.1.2. Commands Used in a Cyclic Symmetry Analysis..................................................................... 164
7.2. Cyclic Modeling............................................................................................................................ 164
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7.2.1.The Basic Sector................................................................................................................... 165
7.2.2. Edge Component Pairs......................................................................................................... 166
7.2.2.1.CYCOPT Auto Detection Tolerance Adjustments for Difficult Cases............................... 166
7.2.2.2. Identical vs. Dissimilar Edge Node Patterns................................................................... 169
7.2.2.3. Unmatched Nodes on Edge-Component Pairs.............................................................. 170
7.2.2.4. Identifying Matching Node Pairs.................................................................................. 170
7.2.3. Modeling Limitations........................................................................................................... 170
7.2.4. Model Verification (Preprocessing)........................................................................................ 171
7.3. Solving a Cyclic Symmetry Analysis............................................................................................... 171
7.3.1. Understanding the Solution Architecture.............................................................................. 171
7.3.1.1.The Duplicate Sector.................................................................................................... 171
7.3.1.2. Coupling and Constraint Equations (CEs)...................................................................... 172
7.3.1.3. Non-Cyclically Symmetric Loading............................................................................... 173
7.3.1.3.1. Specifying Non-Cyclic Loading............................................................................ 174
7.3.1.3.2. Commands Affected by Non-Cyclic Loading........................................................ 176
7.3.1.3.3. Plotting and Listing Non-Cyclic Boundary Conditions........................................... 176
7.3.1.3.4. Graphically Picking Non-Cyclic Boundary Conditions........................................... 176
7.3.2. Solving a Static Cyclic Symmetry Analysis.............................................................................. 176
7.3.3. Solving a Modal Cyclic Symmetry Analysis............................................................................ 178
7.3.3.1. Understanding Harmonic Index and Nodal Diameter.................................................... 178
7.3.3.2. Solving a Stress-Free Modal Analysis............................................................................ 179
7.3.3.3. Solving a Prestressed Modal Analysis............................................................................ 180
7.3.3.4. Solving a Large-Deflection Prestressed Modal Analysis................................................. 181
7.3.3.4.1. Solving a Large-Deflection Prestressed Modal Analysis with VT Accelerator.......... 183
7.3.4. Solving a Linear Buckling Cyclic Symmetry Analysis............................................................... 183
7.3.5. Solving a Harmonic Cyclic Symmetry Analysis....................................................................... 184
7.3.5.1. Solving a Full Harmonic Cyclic Symmetry Analysis........................................................ 184
7.3.5.1.1. Solving a Prestressed Full Harmonic Cyclic Symmetry Analysis............................. 185
7.3.5.2. Solving a Mode-Superposition Harmonic Cyclic Symmetry Analysis.............................. 186
7.3.5.2.1. Perform a Static Cyclic Symmetry Analysis to Obtain the Prestressed State............ 187
7.3.5.2.2. Perform a Linear Perturbation Modal Cyclic Symmetry Analysis............................ 188
7.3.5.2.3. Restart the Modal Analysis to Create the Desired Load Vector from Element
Loads ............................................................................................................................... 188
7.3.5.2.4. Obtain the Mode-Superposition Harmonic Cyclic Symmetry Solution................... 189
7.3.5.2.5. Review the Results.............................................................................................. 190
7.3.6. Solving a Magnetic Cyclic Symmetry Analysis........................................................................ 191
7.3.7. Database Considerations After Obtaining the Solution.......................................................... 192
7.3.8. Model Verification (Solution)................................................................................................. 192
7.4. Postprocessing a Cyclic Symmetry Analysis.................................................................................... 193
7.4.1. General Considerations........................................................................................................ 193
7.4.1.1. Using the /CYCEXPAND Command............................................................................... 193
7.4.1.1.1. /CYCEXPAND Limitations..................................................................................... 194
7.4.1.2. Result Coordinate System............................................................................................ 194
7.4.2. Modal Solution..................................................................................................................... 195
7.4.2.1. Real and Imaginary Solution Components.................................................................... 195
7.4.2.2. Expanding the Cyclic Symmetry Solution..................................................................... 196
7.4.2.3. Applying a Traveling Wave Animation to the Cyclic Model............................................. 196
7.4.2.4. Phase Sweep of Repeated Eigenvector Shapes............................................................. 197
7.4.3. Static, Buckling, and Full Harmonic Solutions......................................................................... 198
7.4.4. Mode-Superposition Harmonic Solution............................................................................... 198
7.5. Example Modal Cyclic Symmetry Analysis...................................................................................... 198
7.5.1. Problem Description............................................................................................................. 199
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7.5.2. Problem Specifications......................................................................................................... 199
7.5.3. Input File for the Analysis...................................................................................................... 200
7.5.4. Analysis Steps...................................................................................................................... 202
7.6. Example Buckling Cyclic Symmetry Analysis.................................................................................. 203
7.6.1. Problem Description............................................................................................................. 203
7.6.2. Problem Specifications......................................................................................................... 203
7.6.3. Input File for the Analysis...................................................................................................... 204
7.6.4. Analysis Steps...................................................................................................................... 207
7.6.5. Solve For Critical Strut Temperature at Load Factor = 1.0........................................................ 208
7.7. Example Harmonic Cyclic Symmetry Analysis................................................................................. 210
7.7.1. Problem Description............................................................................................................. 211
7.7.2. Problem Specifications......................................................................................................... 211
7.7.3. Input File for the Analysis...................................................................................................... 211
7.7.4. Analysis Steps...................................................................................................................... 213
7.8. Example Magnetic Cyclic Symmetry Analysis................................................................................. 216
7.8.1. Problem Description............................................................................................................. 216
7.8.2. Problem Specifications......................................................................................................... 217
7.8.3. Input file for the Analysis...................................................................................................... 218
8. Rotating Structure Analysis................................................................................................................ 223
8.1. Understanding Rotating Structure Dynamics................................................................................. 223
8.2. Using a Stationary Reference Frame............................................................................................... 224
8.2.1. Campbell Diagram............................................................................................................... 225
8.2.2. Harmonic Analysis for Unbalance or General Rotating Asynchronous Forces.......................... 227
8.2.3. Orbits................................................................................................................................... 228
8.3. Using a Rotating Reference Frame................................................................................................. 228
8.4. Choosing the Appropriate Reference Frame Option....................................................................... 230
8.5. Example Campbell Diagram Analysis............................................................................................. 231
8.5.1. Problem Description............................................................................................................. 231
8.5.2. Problem Specifications......................................................................................................... 231
8.5.3. Input for the Analysis............................................................................................................ 231
8.5.4. Analysis Steps...................................................................................................................... 232
8.6. Example Coriolis Analysis.............................................................................................................. 234
8.6.1. Problem Description............................................................................................................. 234
8.6.2. Problem Specifications......................................................................................................... 234
8.6.3. Input for the Analysis............................................................................................................ 234
8.6.4. Analysis Steps...................................................................................................................... 235
8.7. Example Unbalance Harmonic Analysis......................................................................................... 236
8.7.1. Problem Description............................................................................................................. 236
8.7.2. Problem Specifications......................................................................................................... 237
8.7.3. Input for the Analysis............................................................................................................ 237
8.7.4. Analysis Steps...................................................................................................................... 239
9. Submodeling....................................................................................................................................... 245
9.1. Understanding Submodeling........................................................................................................ 245
9.1.1. Nonlinear Submodeling ....................................................................................................... 246
9.2. Using Submodeling...................................................................................................................... 246
9.2.1. Create and Analyze the Coarse Model................................................................................... 247
9.2.2. Create the Submodel............................................................................................................ 248
9.2.3. Perform Cut-Boundary Interpolation..................................................................................... 249
9.2.4. Analyze the Submodel......................................................................................................... 250
9.2.5.Verify the Distance Between the Cut Boundaries and the Stress Concentration...................... 252
9.3. Example Submodeling Analysis Input............................................................................................ 253
9.3.1. Submodeling Analysis Input: No Load-History Dependency................................................... 253
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9.3.2. Submodeling Analysis Input: Load-History Dependency........................................................ 254
9.4. Shell-to-Solid Submodels.............................................................................................................. 259
9.5.Where to Find Examples................................................................................................................ 261
10. Substructuring.................................................................................................................................. 263
10.1. Benefits of Substructuring........................................................................................................... 263
10.2. Using Substructuring.................................................................................................................. 263
10.2.1. Step 1: Generation Pass (Creating the Superelement)........................................................... 264
10.2.1.1. Building the Model.................................................................................................... 265
10.2.1.2. Applying Loads and Creating the Superelement Matrices........................................... 266
10.2.1.2.1. Applicable Loads in a Substructure Analysis....................................................... 268
10.2.2. Step 2: Use Pass (Using the Superelement).......................................................................... 270
10.2.2.1. Clear the Database and Specify a New Jobname......................................................... 270
10.2.2.2. Build the Model......................................................................................................... 271
10.2.2.3. Apply Loads and Obtain the Solution......................................................................... 273
10.2.3. Step 3: Expansion Pass (Expanding Results Within the Superelement).................................. 275
10.3. Sample Analysis Input................................................................................................................. 278
10.4.Top-Down Substructuring........................................................................................................... 279
10.5. Automatically Generating Superelements.................................................................................... 281
10.6. Nested Superelements................................................................................................................ 282
10.7. Prestressed Substructures........................................................................................................... 282
10.7.1. Static Analysis Prestress...................................................................................................... 283
10.7.2. Substructuring Analysis Prestress........................................................................................ 283
10.8.Where to Find Examples.............................................................................................................. 283
11. Component Mode Synthesis............................................................................................................. 285
11.1. Understanding Component Mode Synthesis................................................................................ 285
11.1.1. CMS Methods Supported.................................................................................................... 285
11.1.2. Solvers Used in Component Mode Synthesis....................................................................... 286
11.2. Using Component Mode Synthesis.............................................................................................. 287
11.2.1.The CMS Generation Pass: Creating the Superelement......................................................... 287
11.2.2.The CMS Use and Expansion Passes..................................................................................... 289
11.2.3. Superelement Expansion in Transformed Locations............................................................. 290
11.2.4. Plotting or Printing Mode Shapes....................................................................................... 290
11.3. Example Component Mode Synthesis Analysis............................................................................ 290
11.3.1. Problem Description........................................................................................................... 290
11.3.2. Problem Specifications....................................................................................................... 290
11.3.3. Input for the Analysis: Fixed-Interface Method..................................................................... 293
11.3.4. Analysis Steps: Fixed-Interface Method................................................................................ 297
11.3.5. Input for the Analysis: Free-Interface Method...................................................................... 300
11.3.6. Analysis Steps: Free-Interface Method................................................................................. 301
11.3.7. Input for the Analysis: Residual-Flexible Free-Interface Method............................................ 302
11.3.8. Analysis Steps: Residual-Flexible Free-Interface Method....................................................... 304
11.3.9. Example: Superelement Expansion in a Transformed Location............................................. 305
11.3.9.1. Analysis Steps: Superelement Expansion in a Transformed Location............................ 307
11.3.10. Example: Reduce the Damping Matrix and Compare Full and CMS Results with RSTMAC.... 308
12. Rigid-Body Dynamics and the ANSYS-ADAMS Interface.................................................................. 315
12.1. Understanding the ANSYS-ADAMS Interface................................................................................ 315
12.2. Building the Model...................................................................................................................... 316
12.3. Modeling Interface Points........................................................................................................... 317
12.4. Exporting to ADAMS................................................................................................................... 318
12.4.1. Exporting to ADAMS via Batch Mode.................................................................................. 320
12.4.2.Verifying the Results........................................................................................................... 320
12.5. Running the ADAMS Simulation.................................................................................................. 321
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Advanced Analysis Guide
12.6.Transferring Loads from ADAMS.................................................................................................. 321
12.6.1.Transferring Loads on a Rigid Body..................................................................................... 321
12.6.1.1. Exporting Loads in ADAMS........................................................................................ 322
12.6.1.2. Importing Loads........................................................................................................ 323
12.6.1.3. Importing Loads via Commands................................................................................. 324
12.6.1.4. Reviewing the Results................................................................................................ 324
12.6.2.Transferring the Loads of a Flexible Body............................................................................. 324
12.7. Methodology Behind the ANSYS-ADAMS Interface...................................................................... 325
12.7.1.The Modal Neutral File........................................................................................................ 325
12.7.2. Adding Weak Springs......................................................................................................... 326
12.8. Example Rigid-Body Dynamic Analysis........................................................................................ 326
12.8.1. Problem Description........................................................................................................... 326
12.8.2. Problem Specifications....................................................................................................... 327
12.8.3. Command Input................................................................................................................. 328
13. Element Birth and Death................................................................................................................... 331
13.1. Elements Supporting Birth and Death......................................................................................... 331
13.2. Understanding Element Birth and Death..................................................................................... 331
13.3. Element Birth and Death Usage Hints.......................................................................................... 332
13.3.1. Changing Material Properties............................................................................................. 333
13.4. Using Birth and Death................................................................................................................. 333
13.4.1. Build the Model.................................................................................................................. 333
13.4.2. Apply Loads and Obtain the Solution.................................................................................. 333
13.4.2.1. Define the First Load Step.......................................................................................... 333
13.4.2.1.1. Sample Input for First Load Step........................................................................ 334
13.4.2.2. Define Subsequent Load Steps................................................................................... 334
13.4.2.2.1. Sample Input for Subsequent Load Steps........................................................... 334
13.4.3. Review the Results.............................................................................................................. 334
13.4.4. Use Analysis Results to Control Birth and Death................................................................... 335
13.4.4.1. Sample Input for Deactivating Elements..................................................................... 335
13.5.Where to Find Examples.............................................................................................................. 335
14. User-Programmable Features and Nonstandard Uses..................................................................... 337
14.1. User-Programmable Features (UPFs)............................................................................................ 337
14.1.1. Understanding UPFs........................................................................................................... 337
14.1.2.Types of UPFs Available....................................................................................................... 338
14.2. Nonstandard Uses of the ANSYS Program.................................................................................... 339
14.2.1.What Are Nonstandard Uses?.............................................................................................. 339
14.2.2. Hints for Nonstandard Use of ANSYS................................................................................... 340
15. State-Space Matrices Export............................................................................................................. 341
15.1. State-Space Matrices Based on Modal Analysis............................................................................. 341
15.1.1. Examples of SPMWRITE Command Usage.......................................................................... 341
15.1.2. Example of Reduced Model Generation in ANSYS and Usage in Simplorer........................... 342
15.1.2.1. Problem Description.................................................................................................. 342
15.1.2.2. Problem Specifications............................................................................................... 343
15.1.2.3. Input File for the Analysis........................................................................................... 343
16. Soil-Pile-Structure Analysis............................................................................................................... 347
16.1. Soil-Pile-Structure Interaction Analysis......................................................................................... 347
16.1.1. Automatic Pile Subdivision................................................................................................. 348
16.1.2. Convergence Criteria.......................................................................................................... 348
16.1.3. Soil Representation............................................................................................................ 349
16.1.4. Mudslides .......................................................................................................................... 354
16.1.5. Soil-Pile Interaction Results................................................................................................. 355
16.1.5.1. Displacements and Reactions..................................................................................... 355
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x of ANSYS, Inc. and its subsidiaries and affiliates.