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ANSYS Mechanical APDL Advanced Analysis Guide PDF

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ANSYS Mechanical APDL Advanced Analysis Guide ANSYS, Inc. Release 15.0 Southpointe November 2013 275 Technology Drive Canonsburg, PA 15317 ANSYS, Inc. is [email protected] certified to ISO 9001:2008. http://www.ansys.com (T) 724-746-3304 (F) 724-514-9494 Copyright and Trademark Information © 2013 SAS IP, Inc. All rights reserved. Unauthorized use, distribution or duplication is prohibited. ANSYS, ANSYS Workbench, Ansoft, AUTODYN, EKM, Engineering Knowledge Manager, CFX, FLUENT, HFSS and any and all ANSYS, Inc. brand, product, service and feature names, logos and slogans are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries in the United States or other countries. ICEM CFD is a trademark used by ANSYS, Inc. under license. CFX is a trademark of Sony Corporation in Japan. All other brand, product, service and feature names or trademarks are the property of their respective owners. Disclaimer Notice THIS ANSYS SOFTWARE PRODUCT AND PROGRAM DOCUMENTATION INCLUDE TRADE SECRETS AND ARE CONFID- ENTIAL AND PROPRIETARY PRODUCTS OF ANSYS, INC., ITS SUBSIDIARIES, OR LICENSORS.The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affiliates under a software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, compliance with exporting laws, warranties, disclaimers, limitations of liability, and remedies, and other provisions.The software products and documentation may be used, disclosed, transferred, or copied only in accordance with the terms and conditions of that software license agreement. ANSYS, Inc. is certified to ISO 9001:2008. U.S. Government Rights For U.S. Government users, except as specifically granted by the ANSYS, Inc. software license agreement, the use, duplication, or disclosure by the United States Government is subject to restrictions stated in the ANSYS, Inc. software license agreement and FAR 12.212 (for non-DOD licenses). Third-Party Software See the legal information in the product help files for the complete Legal Notice for ANSYS proprietary software and third-party software. If you are unable to access the Legal Notice, please contact ANSYS, Inc. Published in the U.S.A. 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. iii Advanced Analysis Guide 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information iv of ANSYS, Inc. and its subsidiaries and affiliates. Advanced Analysis Guide 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. v Advanced Analysis Guide 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information vi of ANSYS, Inc. and its subsidiaries and affiliates. Advanced Analysis Guide 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. vii Advanced Analysis Guide 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information viii of ANSYS, Inc. and its subsidiaries and affiliates. Advanced Analysis Guide 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. ix 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 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information x of ANSYS, Inc. and its subsidiaries and affiliates.

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