OptiStruct_Optimization_v13(含拓扑,形貌,尺寸优化).ppt

AltairEngineeringJuly2014 StructuralOptimizationusingOptiStruct Concepts Analysis andOptimizationforGeneralStructures Day1Agenda IntroductionTheoreticalBackgroundOptimizationInterfaceandSetupConceptDesignTopologyOptimizationExercise4a TopologyOptimizationofaHookwithStressConstraintsExercise4b TopologyOptimizationofaControlArmExercise4c PatternRepetitionusingTopologyOptimizationDesignInterpretationOSSmoothExercise4d OSSmoothSurfacesfromaTopologicalOptimizationTopographyOptimizationExercise4e TopographyOptimizationofaL BracketIncludingAutobeadReinterpretationFree sizeOptimizationExercise4f Free sizeOptimizationofFinitePlatewithHole Day2Agenda ReviewFineTuningDesignSizeOptimizationExercise5a SizeOptimizationofaRailJointExercise5b DiscreteSizeOptimizationofaWeldedBracketShapeOptimizationExercise5c CantileverL beamShapeOptimizationExercise5d ShapeOptimizationofaRailJointFree shapeOptimizationExercise5e Free shapeoptimizationCompressorBracketExercise5f ShapeOptimizationofa3 DBracketusingtheFree ShapeMethodOptionalExercisesTopologyExercisesUsingSolidThinkingInspireExerciseA1 GettingStartedUsingInspireExerciseA2 TopologyOptimizationUsingMultipleLoadCasesinInspireCompositeShellElementOptimizationExerciseB1 OptimizingaPlatewithHoleTestCoupon PCOMPP STACK PLY Chapter1 Introduction HyperWorksOverviewOptiStructOverview HyperWorksOverview ModelingAnalysisOptimizationVisualizationReportingPerformancedatamanagement OptiStructinHyperWorks OptiStructOverview FiniteElementsAnalysisBasicanalysisfeaturesLinearstaticanalysis Normalmodesanalysis Linearbucklinganalysis Thermal stresssteadystateanalysisAdvancedanalysisfeaturesFrequencyresponsefunction FRF analysisDirectModalRandomresponseanalysisTransientresponseanalysisDirectModalTransientresponseanalysisbasedontheFouriermethodDirectModalNon linearcontactanalysisAcousticAnalysis StructureandFluid FatigueAnalysis Nand N OptiStructOverview MBDAnalysisKinematicsStaticQuasi staticDynamics OptiStructOptimizationOverview Topology Shape Free shape Size Free size Topography Optimization DesignProcess SolverNeutral IntegratedFEASolver ConceptLevelDesign DesignFineTuning DOE Approximations StochasticStudies LightweightSUVFrameDevelopment OldFrame NewFrame Massreduction 20 Increasetorsionstiffness 31 Weldlengthreduction 50 OptimizationProcessforTorsionLinks Upperandlowerlinkmasswithoutpinsisdownto176lbsfrom240lbs TopologyOptimizationGeometryExtraction TopologyOptimizationStiffnessMaterialLayout TopologyOptimizationDesignSpaceandLoad SizeandShapeOptimizationFine tuningtheDesign Chapter2 TheoreticalBackground OptimizationOptimizationConceptsandDefinitions StructuralOptimizationConcepts TheOptimizationProblemStatement Objective WhatdoIwant minf x alsomin maxf x DesignVariables WhatcanIchange XiL Xi XiUi 1 2 3 NDesignConstraints Whatperformancetargetsmustbemet gj x 0j 1 2 3 MNote Thefunctionsf x gi x canbelinear non linear implicitorexplicit andarecontinuousExample Explicity x x2 2xImplicity3 y2x yx x 0 OptimizationDefinitions Topology isamathematicaltechniquethatoptimizedthematerialdistributionforastructurewithinagivenpackagespaceTopography Topographyoptimizationisanadvancedformofshapeoptimizationinwhichadesignregionforagivenpartisdefinedandapatternofshapevariable basedreinforcementswithinthatregionisgeneratedusingOptiStruct FreeSize isamathematicaltechniquethatproducesanoptimizedthicknessdistributionperelementfora2Dstructure OptimizationDefinitions Shape isanautomatedwaytomodifythestructureshapebasedonpredefinedshapevariablestofindtheoptimalshape Size isanautomatedwaytomodifythestructureparameters Thickness 1Dproperties materialproperties etc tofindtheoptimaldesign Gauge isaparticularcaseofsize wheretheDVare2Dprops PshellorPcomp FreeShape isanautomatedwaytomodifythestructureshapebasedonsetofnodesthatcanmovetotallyfreeontheboundarytofindtheoptimalshape Compositeshuffle isanautomatedwaytodeterminetheoptimumlaminatestacksequence DVsarethepliessequenceofstacking ItisusedforcompositematerialonlydefinedusingPCOMP G orPCOMPP OptimizationTerminology DesignVariables Systemparametersthatarevariedtooptimizesystemperformance DesignSpace selectedpartswhicharedesignableduringoptimizationprocess Forexample materialinthedesignspaceofatopologyoptimization 20 b 4030 h 90 OptimizationTerminology DRESP1SimpleresponsedefinitionMass massfraction volume volumefraction compliance frequency displacement stress strain force compositeresponses weightedcompliance weightedfrequency andcomplianceindex frequencyresponseanalysisresponsesDRESP2ResponsedefinitionusingauserdefinedfunctionDefinesresponsesasfunctionofdesignvariables gridlocation tableentries responses andgenericpropertiesExample Averagedisplacementoftwonodes DRESP3ResponsedefinitionusingauserdefinedexternalfunctionExternalfunctionmaybewritteninC C orFortran Wherex1 x2arenodaldisplacements Response Measurementofsystemperformance s b h t b h mass OptimizationTerminology ObjectiveFunction Anyresponsefunctionofthesystemtobeoptimized Theresponseisafunctionofthedesignvariables Ex Mass Stress Displacement MomentofInertia Frequency CenterofGravity Bucklingfactor andetc ConstraintFunctions Boundsonresponsefunctionsofthesystemthatneedtobesatisfiedforthedesigntobeacceptable minWeight b h b h 70MPat b h 15MPah 2 b OptimizationProblemExample Acantileverbeamismodeledwith1DbeamelementsandloadedwithforceF 2400N Widthandheightofcross sectionareoptimizedtominimizeweightsuchthatstressesdonotexceedyield Furthertheheighthshouldnotbelargerthantwicethewidthb OptimizationProblemExample ObjectiveWeight minm b h DesignVariablesWidth bL b bU 20 b 40Height hL h hU 30 h 90DesignRegion AllbeamelementsDesignConstraints b h max with max 160MPa b h max with max 60MPah 2 b OptimizationProblemExample MathematicalDesignSpace Beamwidth b mm Beamheight h mm OptimizationTerminology FeasibleDesign Onethatsatisfiesalltheconstraints InfeasibleDesign Onethatviolatesoneormoreconstraintfunctions OptimumDesign Setofdesignvariablesalongwiththeminimized ormaximized objectivefunctionandsatisfyalltheconstraints OptimizationTerminology Gradient basedOptimizationStartfromaX0pointEvaluatethefunctionF Xi andthegradientofthefunction F Xi attheXi Determinethenextpointusingthenegativegradientdirection Xi 1 Xi F Xi Repeatthestep2to3untilthefunctionconvergedtotheminimum OptimizationTerminology SensitivityAnalysisDirectLownumberofDvsHighnumberofconstraintAdjointHighnumberofDVsLownumberofconstraintMoveLimitAdjustmentsConstraintScreeningRegionsandTheirPurposeDiscreteDesignVariables Topology Sizeandshape InterpretingtheResults ObjectiveDidwereachourobjective Howmuchdidtheobjectiveimprove DesignVariablesValuesofvariablesfortheimproveddesignConstraintsDidweviolateanyconstraints Interpretingtheresults Whatcangowrong Localminimumvs globalminimumSolutionmightnotbeavailablewiththegivenobjective constraintsanddesignvariables overconstrainedEfficiencyofOptimizationRelationbetweenconstraintsanddesignvariableswrttheirnumbersUnconstrainedOptimizationProblemOptimizationproblemsetupisnotappropriateIssuesrelatedtoFEAmodelingStressconstraintsonnodesconnectedtorigids TheDRCOApproach DesignVariableTheparameters properties orelementsthatOScanchangetoachievedifferentresponsesPrototypicallyusuallyanentirepartorasignificantpartfeatureRepresentedinatradediagramastheareaorn dimensionalvolumeoftheplotResponseAmeasurementofanoutputcharacteristicofthemodeledsystemEmpiricallysampledviasensor oscilloscopeprobe orcomputerimagingsystemRepresentedinatradediagramastheaxesoftheplotConstraintAnumericallimit eitherupperorlowerlimit appliedtoaresponseEitherspecifiedbyexternalguidelines MIL SPEC FAA ISOstandards internalprojectrequirements orcomputedfromphysicallimitationsandcharacteristics E n a r m Representedinatradediagramasaiso line surfaceoradatumline plane formstheboundariesforacceptabledesignsObjectiveAnon numericalindicatoroftheultimategoaloftheoptimizationPracticallylimitedbytime monetaryormanpowerresources availabilityofaccesstodata testingfacilitiesRepresentedinatradediagramastheintersectionofboundaries whichintersectiontopickisdeterminedbywhichresponseistobemaximizedorminimized Chapter3 OptimizationInterfaceandSetup ModelDefinitionStructureOptimizationSetupHowtosetupanoptimizationonHyperMesh OptimizationGUI OptimizationPanel OptimizationMenu ModelBrowser OptimizationSetupmoduleinHyperMesh DefinitionofDesignVariables OptimizationPanel OptimizationMenu ModelBrowser OptimizationView OptimizationSetupmoduleinHyperMesh DefinitionofResponses OptimizationSetupmoduleinHyperMesh DefinitionofDesignConstraint OptimizationSetupmoduleinHyperMesh DefinitionofObjective ModelDefinitionStructure Input OutputSectionSubcaseInformationSectionDefineLoadCases SubCases LoadSteps DefinitionofObjectiveandConstraintReferenceBulkDataSectionOptimizationProblemDesignVariablesResponsesConstraintsOptimizationparameters DOPTPRM FiniteElementModel ModelDefinitionStructure Input OutputSectionASCIIoutput out stat hist sh desvar prop hgdata grid oss HM comp cmf HM ent cmf HTMLReports html frames html menu html shuf html Modelresults res h3d des h3d s h3dHVsessionfile mvw hist mvw ModelDefinitionStructure OptimizationCards Thecompletedescriptionsofthesecardsareavailableattheonlinedocumentation ConstraintandObjectivedefinition DCONSTRDefinesResponsesasoptimizationconstraints Relatesresponsetolowerand orupperboundDCONADDAddsconstraintsundersameidDESSUB DESGLBLoadcasedependent andindependentreferenceinCaseControlSectionDESOBJLoadcasedependent andindependentreferenceinCaseControlSectionMin max OptimizationCards DEQATNDefinesanequationLinkedtoDVPREL2 DRESP2foruserdefinedpropertyorresponse DTABLEDefinesconstantsusedinDEQATNLinkedtoDVPREL2 DRESP2DSCREENConstraintscreeningdefinitionDOPTPRMOptimizationparameterdefinitionsMaxnumberofiterations minimummembersizecontrol movinglimits tolerances ConstraintandObjectiveDefinition LoadCaseReference ObjectiveanddesignconstraintsneedtobedefinedloadcasedependentiftheresponseisareactiontoaloadLoadcasedependentCompliance frequency displacement stress strain force compositeresponsesFunctionsusingtheseresponsesw oloadcaseassignmentLoadcasein dependent global Mass massfraction volume volumefraction centerofgravity momentsofinertia weightedcompliance weightedfrequency complianceindexFunctionsusingtheseresponsesFunctionsusingcompliance frequency displacement stress strain force compositeresponseswithloadcaseassignment OptimizationSetup HowtosetupanoptimizationonHyperMesh OptimizationSetup HowtosetupanoptimizationonHyperMeshStep1 SetuptheFiniteelementanalysis OptimizationSetup HowtosetupanoptimizationonHyperMeshStep2 DefinetheDesignVariables Optimization Create SizeDesvars OptimizationSetup HowtosetupanoptimizationonHyperMeshStep3 DefinetheResponses Optimization Create Response OptimizationSetup HowtosetupanoptimizationonHyperMeshStep4 Definetheconstraints Optimization Create Constraints ThiscreatesontheI OInformationsection Thiscreatesonthebulkdatasection OptimizationSetup HowtosetupanoptimizationonHyperMeshStep5 DefinetheObjective Optimization Create Objective ThiscreatesontheSubcaseInformationsection OptimizationSetup HowtosetupanoptimizationonHyperMeshStep6 RuntheSimulation Application OptiStruct OptimizationSetup HowtosetupanoptimizationonHyperMesh DV DVPREL D DVPR RESPONSE RESP CONSTRAINT OBJECTIVE CONS OBJ Chapter4 ConceptDesign TopologyOptimizationTopographyOptimizationFree sizeOptimization HowStructuralOptimizationCutsDevelopmentTime MostoftheproductcostisdeterminedattheconceptdesignstageProblem minimumknowledge butmaximumfreedomNeed effectiveconceptdesigntoolstominimizedownstream re design costsandtime to market TopologyOptimization Baselinedesign designproposal DesignVariablesTopologyOptimization DensityMethodVeryrobust PenaltyFactorMorediscretedesignproposals WhatdoesOptiStructchange OptiStructInput TopologyOptimization DTPLcard DesignVariabledefinitionfortopologyoptimizationShells PropertywithbaseandtotalthicknessdefinestopologydesignspaceSolids PropertiesdefinetopologydesignspaceComposites PCOMP PropertiesdefinetopologydesignspaceRod Bar Weld Bush PropertiesdefinetopologydesignspaceStressconstraintsboundsManufacturingconstraintsdefinitionHyperMeshTopologypanel TopologyoptimizationonPCOMP Increase decreasethethicknessofgivenplyangleAbilitytooptimizetheangleaswellbycreating phantom ply matoptiononDTPLPly plybasedPCOMP default Homo homogenizedPSHELL TopologyOptimizationusingManufacturingConstraints WhatareManufacturingConstraints AdditionalinputfortheoptimizationproblemOptiStructtriestomeetmanufacturingconstraintsWhyaretheysoimportant MakeitmucheasiertointerpretoptimizationresultsUseofstandardprofiles manufacturingtools processesOptimizedstructuresareofnovalueifnobodycanmanufacturethemImplementedmanufacturingconstraintsMaximummembersizeMinimummembersizeDrawdirectionconstraintPatternrepetitionPatterngroupingExtrusionconstraint TopologyOptimizationusingManufacturingConstraints ManufacturingconstraintsfortopologyoptimizationhelpsgeneratepracticaldesignconceptsMinimummembersizecontrolspecifiesthesmallestdimensiontoberetainedintopologydesign Controlscheckerboardeffectanddiscreteness Maximummembersizecontrolspecifiesthelargestdimensionallowedinthetopologydesign Itpreventslargeformationoflargemembersandlargematerialconcentrationsareforcedtomorediscreteforms Patterngrouping repetitioncanbeappliedtoenforcearepeatingpatternorsymmetricaldesigneveniftheloadsappliedonthestructureareunsymmetricalornon repeating Drawdirection extrusionconstraintscanbeappliedtoobtaindesignsuitableforcastingormachiningoperationsbypreventingundercutordie lockcavities ManufacturingConstraints MinimumMemberSizeControl Input approximateminimumdiameterdintwodimensionsWorksin2Dand3DControlsthesizeofsmallstructuralfeaturesControls checkerboarding EasierinterpretationoftheresultinglayoutHighercomputationcost d 60 d 90 WithoutminmembersizeDifficulttomanufactureduetomicrostructuresResultsaremeshdependent ManufacturingConstraints MaximumMemberSizeControl DefinitionofmaximumallowablestructuralmembersizeEliminatesmaterialconcentrationsMeshconsiderationsShellandsolidelementsTetrahedralandhexhedralMinmember 3XmeshsizeMaxmember 2Xminsize WithoutMaximumMembersize WithMaximumMembersize ManufacturingConstraints PatternRepetition CyclicRepetitionSymmetrydefinitionsCyclicrepetitionofdesignfeatureswithinasingledomainUserenters ofwedgesApplication Cyclicstructureswithnonsymmetricalloadcases PatternRepetition Applicationexample AirplaneWingRibsGoal sametopologyoneveryribScalingfactortoaccountfordifferentsizesofdesignspace PatternRepetition Applicationexample AirplaneWingRibs Withoutpatternrepetition Withpatternrepetition DrawDirectionConstraint DefineglobalcastingdirectionEliminatesundercutsindesignproposalReducesinterpretationeffortImportantifpartshallbemanufacturedbyCastingInjectionmoldingMillingDrawtypeoptionsSingleSplitTheobstacleswitchallowsformeshtobespecifiedwhichformsanobstacletothedrawprocess directingthesolvertoadjustthesolutionaccordingly DrawDirectionConstraint Example DetermineOptimumStiffenersinTorsionLoadedU Profile InitialStructure OptimizationModel OptimizationResults WithoutDrawDirection WithDrawDirection DrawDirectionConstraint Example OptimumRibPatternofaControlArm WithDrawDirection WithoutDrawDirection ExtrusionConstraint Manufacturingcontrolforconstantcrosssections Packagespace Designproposalwithoutextrusionconstraint Designproposalwithextrusionconstraints CombinationofManufacturingConstraints Anycombinationofmanufacturingconstraintsispossible PatternGrouping Symmetry DrawDirection Symmetry DrawDirection ApplicationsofTopologyOptimization DeterminationofOptimumRibPatternsforReinforcement NondesignspacerepresentsgeneralgeometryconceptDesignspacedefinesareaswhereribsshallbeintroducedManufacturingconstraintscrucialDrawdirectionMinimum maximummembersize CommonTopologyOptimizationProblems Minimize weighted total regional compliancewithconstrained total regional volume massfractionMinimize total regional volume massfractionwithconstraineddisplacementsMaximize weighted frequencywithconstrained total regional volume massfractionMinimize total regional volume massfractionwithconstrainedfrequenciesMinimizecombinedcomplianceandfrequencieswithconstrained total regional volume massfractionMinimize total regional volume massfractionwithstressconstraints AdditionalOptimizationConsiderations ConstraintScreening DSCREEN Screening specifynormalizedthresholdvalueTemporarilyignoresconstraintswhicharelessthanthenormalizedthresholdvalueduringoptimizationRegionalization specifymaximumnumberofconstraintstoberetainedforagivenregionConsidersuserspecifiednumberofmostviolatedconstraintsforeachloadcaseandregionid EssentialinsituationswheretherearemanyconstraintsE g Stressconstraintsforshape sizeoptimization Iftoomanyconstrainedresponsesarescreened itmaytakeconsiderablylongertoreachaconvergedsolutionor intheworstcase itmaynotbeabletoconvergeonasolutionifthenumberofretainedresponsesislessthanthenumberofactiveconstraintsforthegivenproblem TopologyOptimizationwithstressConstraints GlobalvonmisesstressconstraintsApplytoentiremodelincludingnondesignspaceStressconstraintsforapartialdomainofthestructurearenotallowedThereasonisthatitoftencreatesanill posedoptimizationproblemaseliminationofthepartialdomainwouldremoveallstressconstraintsLocalstressesarestillhighThisisforgeneralstresslevelcontrolLocalstressshouldbetakencareofbyusingshape size Stress 50 Stress 30 Exercise4a TopologyOptimizationofaHookwithStressConstraints InthisExercise atopologyoptimizationisperformedonabracket hookmodeledwithshellelementsusingHyperMeshDesktopandOptiStruct Exercise4a ManualPage65 TopologyOptimizationofaHookwithStressConstraintsFileNameandLocation ModelFiles 4a TOPOLOGY HOOK STRESS CONSTRAINT hook femObjectives ImporttheSolverDeckintoHyperMeshDesktopCreatetheTopologyDesignVariableCreatingtheOptimizationResponsesCreatingtheOptimizationConstraintsCreatingtheObjectiveRunningtheOptimizationPost ProcessingtheOptimization Do it yourself Do it yourself ExerciseSteps 1 LaunchHyperMeshDesktopandSet