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VolumeVIII-Winter2018|73Co-simulation-BreakingtheBackofMultiphysicsCAESimulationByDr.
KeithHanna,VicePresidentMarketing,MSCSoftwareOverthelast20yearsorso,oneofthe'holygrails'ofcomputer-aidedengineering(CAE)hasbeen'multiphysics'simulations,i.
e.
co-simulationsbetweendifferentphysicssimulationtypes(Ref.
1).
Multiphysics,eventhoughanill-definedterm,kindoffeelsintuitivelyrighttousengineersfromtheperspectiveofreal-worldengineeringsimulation.
Fluidsdon'tusuallyexistinisolationfromstructuraleffects,oracoustics,ordynamicsintherealworldweinhabit,yetformanyyearspast,engineershavesimulatedthesesubdomainsofphysicsasisolatedpointsimulationsolutionsinCAE.
IhavetoaddariderherethatmyPhysicsteacheratHighSchool,MrCopeland,wouldhavetakenmetotaskforusingtheword'multiphysics'atallbecausestrictlyitiswrong.
Thereisactuallyonlyonedisciplineofphysics,asthereisforchemistryandbiology.
WithinphysicstherearesubdisciplineslikeNewtownianLawsofMotion(andfluids),Maxwell'sLawsofAdams-scFLOWpredictionofdynamicvehiclesuspensionmovementinacrossflowwind74|EngineeringRealityMagazineElectromagnetics,StructuralStress-Strainlawsetc.
This'multiphysics'wordthatwascoinedinthe1990sisactuallyaconsequenceofafailureoftheCAEindustrytosolvethefundamentalunderlyingphysicsequationsinacombinedwayinmyopinion.
Partly,thisisduetopracticalproblemsthatwefindbecauseofdifferentmathematicaltechniques.
Forinstance,FiniteVolumeMethods(bestforfluids),FiniteElementMethods(bestforstructuresandacoustics)meanthatformoreefficientsolverconvergenceinrealworldengineeringproblems,oneortheotherischosenasthebestmethodology.
Andpartly,softwarevendorshavestruggledtograpplewiththemultiphysicschallengetodeliverusableengineeringsimulationtoolsbecausethemathematicalapproachesdon'ttendtogelwelltogetherwhencombined.
Figure1:MSC'sUniqueMultiphysicsCo-SimulationCapabilitiesTable1:ACrossSectionofCo-SimulationCAEapplicationsconnectedtotheMSCSoftwareSolutionSuiteVolumeVIII-Winter2018|75WhatwasverystrikingaboutMSCSoftwarewhenIjoinedearlierthisyear,apartfromits50+yearhistorystretchingbacktotheearlyNASAmoonlandingproject,andthedesireforaccuracyinsoftwaresolutions,isalargelyunderstatedhistoryofendeavoringtoprovideworldclassCAEco-simulationsolutionstoitscustomersaswellasengineerseverywhere.
Everythingfromacousticstomultibodydynamics(MBD),toCFD,tostructuralanalysis,andexplicitcrashdynamicscanbeconnectedtogetherinMSC(seeFigure1).
Ihavegatheredtogetheramultiplicityofmultiphysicsco-simulationapplicationsthatcanbedonewithMSCsoftwaretoolstoday,bothintwo-productcouplings,aswellasintoolchainsofproductsimulationsthatweremerepipedreamsafewyearsago(seeTable1).
MultiBodyDynamicsLedCo-SimulationWhenonedigsdownonesoondiscoversthatthemarketleadingAdamsMBDproductisbeingusedextensivelyforindustrialgradeco-simulationsaroundtheworldtodayasamatterofcourse,andisopentoconnectionswithallsortsofcommercialandopen-sourcesoftware(seeFigure2).
SomenotablerecentinnovationsareconnectionstothemarketleadingDiscreteElementModelingsoftware,EDEM,fromDEMSolutions,asillustratedbyFigure3,VIRESVirtualTestDrive(VTD)forADASandautonomousvehicledrivesimulation(VIREShasbeenpartofMSC/Hexagonsince2017),andofcourseMATLAB&SIMULINKfor0D/1Dsystemsandcontrolsmodeling(fromMathWorks).
AdamscoupledwithMarccansolvewiperblademovements,hydraulicFigure2:MSC'sAdamsMBDCo-SimulationCapabilityEcosystemFigure3:MSC'sAdamsMBDCo-SimulationCapabilitywithEDEMfromDEMSolutionsFigure4:MSC'sNastran–scFLOW-MarcCo-Simulationofaflapbendingandtwistinginacrossflowactuators,rubberdoorseals,andfullvehiclebushmodeling.
Iwillgointomoredetailbelowabouttheexcitingnewco-simulationmultiphysicscapabilitiesthattheCFDsoftwareacquisitionofSoftwareCradlebyMSCSoftwarein2016isnowbeginningtoopenupforCFDandCAEengineersalike.
Averycomplexandchallengingdynamicco-simulationisshowninFigure4whereanon-linearbendingandtwistingmetallicflapinacrossflowwassimulatedinanscFLOW-Marc-MSCNastrantoolchain.
AcousticsLedCo-SimulationActranisrecognizedtobethemarketleaderinacousticssimulationwithatwenty-yearhistorybehinditandabluechipuserbaseworldwide.
IthasmanymultiphysicsacousticapplicationsliketheclassiconeofcouplingwithCFDforaeroacousticanalysis.
Actranprovidestodayacompleteend-to-76|EngineeringRealityMagazineendsolutionfrommechanicalloadpredictiontonoiseandvibrationassessment.
InarecentWebinar(Ref.
2)mycolleaguesRomainBaudsonandYijunFanlookedatacousticpredictionsforelectricvehicleswithActranledtoolchains.
Figure5showsthetwotoolchainstheyemployedintheirco-simulationanalyses.
MultibodysimulationwithAdamsprovidesthestructuralloadswhentheconventionalpowertrainisoperating,thenMSCNastranwasusedforvibrationanalysis.
Finally,noiseradiationisthencomputedwithActranwithhighaccuracyinafullyautomatedprocess.
Bycomparison,forElectricVehicles,electromagneticsimulationresultsfromvariousthirdpartysoftware(forexample,JMAG,MagNet,Maxwell…)canbeintegratedwithMSC'sFEAtoolsforelectricmotornoiseprediction.
InsodoingActranprovidesaccuratenoisepredictionsforboththeelectricmotorandthegearreducer.
Finally,arelativelyrecentacousticsandfluidsco-simulationisillustratedinFigure6betweenActranandscFLOWfromSoftwareCradlewhereanautomotiveexhaustandmufflersystemwasmodeledinCFDandcoupledwithActranforacousticnoiseprediction.
CFDLedCo-SimulationComputationalFluidDynamics(CFD)haslongbeenapassionofmineanditisgenuinelyquiteexcitingtoseewhatishappeninginJapanwithSoftwareCradle'sco-simulationCFDefforts.
Theyhavedevisedaremarkablyrobustandopensoftwareplatformforco-simulation(seeFigure7).
SoftwareCradle'sCFDproducts–scFLOW(thatemployspolyhedralmeshes),scSTREAM(withCartesianmeshes)andSC/Tetra(withtetrahedralmeshes)havealonghistoryofusebylargeOEMsandleadingJapanesecompaniesandcomewithastrongtechnicalFigure5:MSC'sAdams–NastranandActranConventionalAutomotivePowertrainCo-SimulationToolchain(left)andE-Mag–Nastran–Actrane-PowertrainToolchainforAcoustics(right)Figure6:MSC'sCradleCFDandActranAcousticsco-simulationforanAutomotiveExhaustandMufflerAeroacousticsPredictionVolumeVIII-Winter2018|77pedigree.
Theyaretechnologyleadinginfreesurfaceandoversetmeshingtechniqueswithfast,accurateandrobustapproaches.
PhysicalquantitiescanbepassedbetweenthirdpartyandMSC'sCAEsoftwareandCradle'sCFDtoolsusingitsFMI(FunctionalMockupInterface).
TheFMIsupportsgeneralphysicalquantitysettings,user-definedfunctions,andscriptlanguages.
WithAdamsinparticular,thisco-simulationapproachcandolargeparticulateflowsonfreesurfaces(Figure8),vanepumps,washingmachinedrumvibration,andMBDfueltanksloshing(Figure9)forinstance.
AreallyexcitingMBDapplicationisthatofavehicledrivingthroughalargepuddlewithsuspensioneffectstakenintoaccountbyAdamsorthesamevehicle'sdynamicsinacrosswind(Figure10).
Co-simulationwithMarcmeansthatCradleCFDcouplingscandoaircraftfueltankbaffles,liquidquenching,flexibleplates/membranes/valveseals(Figure11),andSiroccofans.
WhencoupledtoMSCNastran,scFLOWcandoFSIofship'spropellerwithcavitationeffectsincludedforexample(seeFigure12).
It'sthereallycoolco-simulationCFDapplicationsthatcatchyoureyethemost,however.
SoftwareCradlehavecoupledAdamswithscFLOWtolookatdynamicaircraftwingandflapdeploymentaerodynamicFigure7:SoftwareCradle'sOpenCouplingCFDPlatform(Left)andFMIInterfaces(Right)Figure8:Adams–scSTREAMpredictionoflargelogsinachannelfreesurfaceflowFigure9:Adams-scFLOWpredictionofdynamicsloshingofliquidinatankFigure10:Adams–scSTREAMpredictionofadynamicvehiclesuspensionmovementthroughapuddleFigure11:FSIanalysisusingMarcandscFLOWofaValvewithanElasticMembranedeformedbyflowFigure12:MSCNastran-scFLOWpredictionofpropellerwithfreesurfaceandcavitationFigure13:Adams-scFLOWdynamicpredictionofwingflapdeploymentaerodynamics(abovetop)andavibratingsupersonicplateshockstructureco-simulationinMSCNastran–scFLOWCFD(abovebottom)78|EngineeringRealityMagazinepredictions(seeFigure13).
Anotherexcitingnewaerodynamicco-simulationapplicationbetweenscFLOWandMSCNastran/Marcisnon-linearpanelflutterofasupersonicplate(Ref3),involvingahighlyunusualcoupledundulatingvibrationoftheflatplate'ssurfaceathighspeedsresultinginmovingshocksonthesurface(seeFigure13).
ItwasaccomplishedbymycolleagueFaustoGilldiVincenzoinItalywhoemployedourseamlessMSCNastran-scFLOWCFDcouplingtechnologyforanefficientandfastsolution.
TheCFDdomaindeformationpredictionwasdonewithslidingmeshcapabilitiesandthentheFEAwasperformedbyMSCNastranandMarc.
TheCFDelementsusedcouldbetets,hexas,orpolyhedralelements.
Finally,anotherareaofinterestofmineisthermo-mechanicalstresspredictionsforelectroniccomponentsonchipsandPCBs(PrintedCircuitBoards).
Thisapplicationtooisquitedifficulttodoasaco-simulationbymostcommercialvendors.
InFigure14anelectronicchipresistorhasbeensimulatedthatundergoesrepeatedheatgenerationbyitsownon-offactions(Ref.
4).
Thiswilleventuallycausethebreakageofitssolderjointsoverthelifetimeofthecomponentandultimatelyproductfailure.
Beingabletopredictitinadvanceandtolocatehighstressareasisveryimportant.
TemperaturedistributionpredictionsfromscSTREAMweremappedontothemeshofthestructuralanalysissolver(egMSCNastranorANSYSMechanical).
Thestressonthesolderconnectionwasthenpredicted.
ThisisaverypowerfulwayofpredictingfailuremechanismsandtheirlikelylocationsintheconsumerelectronicsindustryandisrelativelyeasytodoinscSTREAMasaco-simulation.
VolumeVIII-Winter2018|79Figure14:scSTREAMthermo-mechanicalstresspredictionofelectroniccomponentsolderstressesSummaryClassical'multiphysics'challengesforCAEincludefluidsandstructures(FSI,VIV),structuresandacoustics,structuresanddynamics,andfluidsanddynamics.
MultiphysicssimulationmaysoundeasyinprincipleyetmanycommercialCAEvendorshavehadpointphysicssolutionsfordecadesnowbuthavefailedtoimplementusablecoupledsolutionsforindustrialgradeengineeringapplication(eitherloose-orclosely-coupledCAE).
So,'multiphysics'isstilloneofthe'HolyGrails'ofCAEsolutionevenafter40to50yearsofpointsimulationsinallthephysicssub-disciplines.
MSCSoftwarehasgrappledwiththisco-simulationconundrumandcomeupwithmanyusablesolutionsandtoolchainsforrealworldengineeringapplications.
IwouldencourageyoutoexplorewhatweofferanduseMSCOnecreditstotrythemout.
AskyourlocalMSCaccountmanagerorsupportengineerifyouwanttoknowmore.
WeofferboththetechnologiesandtheprofessionalservicesthatcanhelpyousolveyourindustryCAEco-simulationchallenges.
References1.
"BacktotheFuture;TrendsinCommercialCFD"byJ.
Parry&K.
Hanna,NAFEMSWorldCongress,Boston,USA,2011:http://s3.
mentor.
com/public_documents/whitepaper/resources/mentorpaper_90428.
pdf2.
"NoisePredictionforElectricPowertrain"Webinar,byR.
BaudsonandY.
Fan,August2018:http://www.
mscsoftware.
com/events_assets/Webcasts/2018_Webinars/noise-prediction-for-electric-vehicle-powertrain.
html3.
"AnEfficientFluidStructuralWorkflowusingtheSeamlessCouplingTechnology"Webinar,August2018:http://www.
mscsoftware.
com/events_assets/Webcasts/2018_Webinars/an-efficient-fluid-structural-workflow-using-the-seamless-coupling-technology-within-msc-nastran-marc-and-sc-tetra.
html4.
"PredictingDurabilityofJunctionsforMountedParts"CradleCFDCaseStudy:https://www.
cradle-cfd.
com/images/applications/electronics/11ST_MountedPartsDurability_email