Innovation Intelligence®Simulation Driven NVH DesignHarold Thomas, Ph.D.Program DirectorAltair Engineering, Inc.thomas@alt...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.AMSES Eigensolver• NVH problem...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.OptiStruct EigenSolver for NVH...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.OptiStruct EigenSolver for NVH...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Performance against Lanczos on...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.EIGRA features• Standard featu...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.1. Help to understand which at...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.• Transfer path analysis (TPA)...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.• Implemented a new mathematic...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.FrFfFrFfFtFeResults can be vie...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.FASTFR Performance against Reg...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2013 Altair Engine...
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engine...
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Simulation Driven NVH Design

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Simulation Driven NVH Design

  1. 1. Innovation Intelligence®Simulation Driven NVH DesignHarold Thomas, Ph.D.Program DirectorAltair Engineering, Inc.thomas@altair.com
  2. 2. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.There is a Need to Reduce Design Verification Time• Competition requires us to the shorten design cycle• The time between the generation of the design and the manufacturing ofthe tooling is reduced• This puts pressure on the analysis team to verify the design in a shorttime• If flaws are found in the design, there must be a rapid determination ofthe cause and possible suggestions for the cure.
  3. 3. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Reducing Time spent Debugging the FE ModelCommon Statement: We don‘t have time to debug and fix the model!• GROUNDCHECK not only shows that model is not good but alsospecifies the elements that are causing the problem• MECHCHECK is used to find mechanisms which are usually caused bymodeling errors• .cmf file is created showingelements that have low quality• .interface file shows fluid-structure coupling
  4. 4. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Reducing Time spent Debugging the FE ModelCommon Statement: We don‘t have time to debug and fix the model!• No PARAM,BAILOUT to mask modeling errors• Erroneous RBE3 elements are detected• Spiders connected to solids with rotational DOF• Free spiders not connected to any structure• Understandable Error messages point to specific problems with themodel*** ERROR # 772 ***It is invalid to use a free grid as an independent grid in RBE3 data.Free spiders are not allowed to be independent grids in RBE3 data.RBE3 id = 10grid id = 11free components = 123• Time spent debugging models with wrong results is reduced from daysto minutes
  5. 5. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.AMSES Eigensolver• NVH problems require an eigensolver that can calculate thousands formodes for problems with millions of DOF• Lanczos is not a solution• The eigensolver must have special features for NVH• Load vector reduction to modal space• Fluid-Structure Coupling (Area) matrix reduction to modal space• Structural Damping (GE) matrix reduction to modal space• Residual Vector (RESVEC) generation• Must be able to handle free-free structures with automatic PARAM,INREL,-2• Solutions for frequency response, transient response, and CMS SuperElement creation• Must SMP parallel for efficiency
  6. 6. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.OptiStruct EigenSolver for NVH• OptiStruct now has an efficient EigenSolver for NVH problems• New EIGRA data is used• Similar to EIGRL data (see next slide)• Has accuracy control (AMPFFACT)• Increased accuracy will increase run times• Automatically increased for powertrain (solid) models• The number of CPU’s used is the same as the number used by OptiStruct• Controlled by –ncpu or –nproc command line arguments• Works on both Windows and LINUX computers• No issues with unconnected structures• Typical of CMS Super Elements created with the CBN method• No additional draw of HyperWorks Units (Still just 25)• No additional license or installation
  7. 7. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.OptiStruct EigenSolver for NVH input dataEIGRABulk Data EntryEIGRA – Real Eigenvalue Extraction Data using Automated Multi-Level Sub-structuringDescription:Defines the data need to perform eigenvalue analysis with the Automated Multi-Level Sub-structuring techniqueFormat:(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)EIGRA SID V1 V2 ND AMPFFACT NORM
  8. 8. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Performance against Lanczos on PCAMSES VS Lanczos for Modal FRF solution0 10000 20000 30000 40000 50000 60000 70000 80000AMSESLanczoselapsed time (s)Eigen SolutionStructral DampingOther EIGRA reduces both Area and Damping matrices EIGRA supports the internal residual vector calculationtechnique to enhance solution accuracy• 2.2 Million Degree of freedom, 1369 modes, w/ structural damping, 200 excitation frequencies, 1CPU• Dell T7500, Xeon X5550 2.67GHz, 12GB RAM, regular disk, 64bit Windows Xp
  9. 9. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.EIGRA features• Standard feature of OptiStruct (same as EIGRL)• Runs on both Windows and LINUX computers• Runs quickly on local workstations• Uses just 25 HyperWorks Units• Can be used for NVH problems
  10. 10. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Reducing Analysis Run TimesCoarse Display ModelDetailedMeshCoarseDisplayMesh
  11. 11. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Reducing Analysis Run TimesCoarse Display ModelResults onDetailedMeshResults onCoarseDisplayMesh
  12. 12. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.1. Help to understand which attachment points dominate the response2. Help to understand if the high response contribution is due to- High transfer function- High force- High local point mobility3. If transfer function is high relative to each other or to generic targets- Reduce transfer function4. If force is high- Re-tune mount rates to rebalance forces5. If local point mobility is high- Increase local stiffnessWhy Perform Transfer Path Analysis
  13. 13. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.• Transfer path analysis (TPA) is a complicated, and error prone process thatinvolves two separate runs and post processing tool:• First run - Calculate unit input Transfer Functions (response from each load)and the Point Mobility (Velocity of the loaded point).• Requires hundreds of subcases (requires automation)• Results in a huge punch file. The input file has to be created from using automationbecause there are so many subcases.• Second run – Calculate Operating (Reaction) Forces using the full vehiclemodel at all loading frequencies.• Results in a huge punch file• Extra computation of path contribution in the post processing tool.• Path Participation = Transfer Function X Reaction Force• Lots of book keeping needed for the post-processing tool• It is computationally expensive to create the above punch filesThe Two Step Process
  14. 14. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.• Implemented a new mathematical formulation by taking advantage ofcertain system matrix characteristics. The computational time is alsoreduced dramatically.• Transfer path participation is directly calculated in the full vehicle rununder the operating load. Computational time for post processing toolis saved.• Very easy to setup the input data.• Transfer function, point mobility, reaction force at each connectionDOF, and partial contribution to each response by every connectionDOF will be in one compressed file (.h3d file)• PEAKOUT card can be used to calculate only at the filtered peakfrequencies.• Computational time is reduced from days to hours.The One Step Process
  15. 15. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.FrFfFrFfFtFeResults can be viewed in NV Director
  16. 16. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Detailed Output at Peak Response FrequenciesOperating Deformed Shape and Participation Output• It takes too long and uses too much disk space to get the operating deformedshape and participation output at each frequency• The engineer has manually determine the problem frequencies, specify thesefrequencies in the input data, and submit a second run• OptiStruct PEAKOUT data automatically determines the critical frequencies andgenerates the operating deformed shape and modal, grid, and panel participationoutput in a single run Peak Frequencies
  17. 17. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Fast Modal Solution with Damping• OptiStruct FASTFR solver• Fast Frequency Response Solution based on Thousands ofModes with Viscous and/or Structural Damping• Modal Damping can also be present with sparse structuraldamping and/or viscous damping• Works with Frequency Dependent Structural Materials(PBUSHT) and frequency dependent fluid properties (PAABSF)• Can be used with coupled fluid-structure (NVH) analysis with fluidmaterial (MAT10 GE) damping• Available for enforced motion (SPCD)• Multi-threaded with nearly linear speedup• No Additional Cost• Runs on Windows and Linux
  18. 18. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.FASTFR Performance against Regular SolutionNumber of ModesSecondsLarge trim body model with 96 subcases with material damping 4 cpus0200004000060000800001000001200001400001600008774 12105Comparison of FASTFR to Regular SolutionREGULAR SOLUTIONFAST FR
  19. 19. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Reducing Analysis Run TimesCMS Super Elements• Fast CMS Super Element creation using AMSES• Includes viscous and structural Damping• Combined Fluid-Structure Super Element is available• Residual Run Results are Line on Line with full mesh analysis• Only a single H3D file is required for each Super Element• Analysis time reduced from hours to minutes• Can be run on a laptop• Allows for quick re-analysis• Allows for optimization
  20. 20. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2013 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Optimization DisciplinesTopographyTopology Free SizeFree Shape SizeShape
  21. 21. Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.OptiStruct for Reducing Design Verification Time• Debugging and fixing the finite element model• GROUNDCHECK and MECHCHECK• Modeling errors detected and reported with understandable messages• Elimination of numerical issues• Reducing analysis run time• PEAKOUT results selection• 1 Step Transfer Path Analysis• AMSES with coarse model 2D PLOTEL elements• Parallel modal system of equations solutions (FASTFR)• Single file based CMS Super Element Analysis• Optimization with CMS Super ElementsFrFfFrFfFtFe
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