NVH轮胎建模规范

Q/SZJ191001-2017NVH轮胎建模建模规范ModelingSpecificationOfTireandWheelForNVH20XX20XX-XX-XX实施20XX-XX-XX发布XXXX汽车工程技术有限公司发布Q/SZXX-X-2017NVH轮胎建模规范范围本标准规定了NVH轮胎建模方法。本标准适用于CAE部门轮胎NVH模型建模。规范性引用文件下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本（包括所有的修改单）适用于本文件。有限元网格建模规范CAE整车模型命名规范术语和定义无。摘要Abstract轮胎供应商已经使用复杂的有限元分析模型来模拟轮胎行为，但他们通过需要的模型自由度数目过于庞大，并不适用于整车噪声与振动分析。对于整车分析，需要相对简单的建模方法，即模态轮胎模型。该模型可用于抓取轮胎/悬架的跳跃、踏步模态，转向系统模态和侧向模态等。轮胎结构比较复杂，见下图所示。因此轮胎的机械性能具有高度的非线性和非弹性，影响因素有尺寸、构成、预载荷、气压、频率、温度、静止或滚动、静态或动态。Sophisticatedfiniteelementmodelshavebeenusedbytiremanufacturerstosimulatetirebehavior.Theyusuallyrequirelargenumbersofdegreesoffreedomandspeciallytailoredsolutiontechniqueswhicharenotsuitableforfullvehiclenoiseandvibrationanalysis.Forfullvehiclenoiseandvibrationanalysisarelativelysimplemodelingmethodiscurrentlyused:themodaltiremodel.Itisprimarilyusedtocapturetire/suspensionhop,tramp,steerandlateralmodes.Thetiresusedinmodernautomobileshavecomplicatedconstruction,asshowninfigurebelow.Therefore,themechanicalpropertiesofthetirearehighlynonlinear,inelasticanddependonmanyfactorssuchastiresize,construction,pre-load,airpressure,frequency,temperature,motionstatusofrollingornon-rolling,staticordynamic.图1轮胎结构模态轮胎模型通过缩减非线性轮胎有限元模型到模态空间后获得，此模型可由轮胎供应商提供。模态轮胎适用于整车噪声和振动分析，最高频率至150Hz。值得注意的是：要建立模态轮胎模型，一般需要花费供应商数周或数月的时间。Amodaltiremodelisobtainedbyreducingadetailednon-lineartireFEMmodeltomodalspaceandisprovidedbytiremanufactures.Amodaltiremodelisappropriateforvehiclesystemnoiseandvibrationanalysisupto150Hz.Itshouldbenotedthat,whenplanningtobuildasystemmodel,ittypicallytakesfromseveralweekstoseveralmonthsforthesuppliertorespondtothesystemanalyst’srequestforamodaltiremodel.流程图建模建模InitiateModeling已有模型？ModelExists?联系供应商Contactmodaltiremodelliaisontodetermineifmodelalreadyexists完成并发布需求给供应商Completeandsubmitrequestformtoliaison等待模型完成Waitformodelcompletion使用模型UseModel否NO图2流程图工具描述ToolDescription仿真分析过程中需要用到的如下软件:Thefollowingsoftwarefacilitatestheanalyticalsimulationprocess:前处理(Preprocessors):Hypermesh求解器(AnalysisCode):Abaqus/Nastran后处理(Postprocessors):HyperView建模和分析过程Modeling/AnalysisProcedure单位Units分析中所用单位制如下所示:Theunitsusedintheanalysisareasfollows:力(Force) 牛顿(N)质量(Mass) 吨(Ton)长度(Length) 毫米(mm)时间(Time) 秒(Second)内容Contents简化后的轮胎模型包括：模态质量、刚度、阻尼和几何表示的轮胎轮廓和连接点（转向节主轴安装孔心、接地点）Thecontentsofthesimplifiedtireandwheelmodelshouldincludealumped-parameterrepresentationofthetireandwheel,includingmodalmass,stiffnessanddampingandgeometricrepresentationoftirecarcassandinterfacepoints,includingthewheelspindleandtirepatchorroad-interfacepoints..坐标系CoordinateSystems模型使用局部坐标系。每个不同位置的轮胎对应一个局部坐标系。局部坐标系的原点在未变形轮胎的几何圆心处。局部坐标系建立步骤如下：X轴是整车坐标系的前后方向，指向从前到后；Y轴是整车的侧向，指向从左到右；Z轴是整车垂向，指向从底到上。Themodelsshouldbesuppliedinlocalcoordinates.Onecoordinatesystemdefinitionshouldbeusedforeachtiremodel.Thecoordinatesystemoriginshouldresideatthegeometriccenteroftheun-deformedtire.Thecoordinatesystemshouldbedefinedasfollows:X-axisshouldcorrespondtovehiclefore/aft,withdirectionfromfronttorear,Y-axisshouldcorrespondtovehiclelateral,withdirectionfromlefttoright,andZ-axisshouldcorrespondtovehiclevertical,withdirectionfrombottomtotop.建模技巧ModelingTechniques模态轮胎模型来源于详细的非线性有限元模型，包括轮胎和车轮。设置好合适的预载、胎压和其他条件后，从详细有限元模型中提取超过200Hz的模态分析结果。在通过Craig-Bampton或其它方法进行模态缩减，即将详细有限元模型规模庞大的物理节点自由度缩减到有限数目的模态自由度，在NASTRAN中通过SPOINT单元来实现。每一对SPOINT单元对应一阶模态。在NASTRAN中，模态轮胎模型包括以下单元：CMASS3、CELAS3和CDAMP3，一起组成弹簧-质量-阻尼系统来代表每一阶模态，在同MPC来连接SPOINT到保留的物理节点。模态质量CMASS3和模态刚度CELAS3由动态缩减过程直接得到。而模态阻尼CDAMP3由模态试验得到。对于整车分析，只有两套物理节点需要保留在模态轮胎模型中：连接车轮的转向节主轴点；轮胎接地点。其中接地点数目一般为9或更多。接地点数目由轮胎加上预载后与地面接触的长度决定。接地点数目的增加要对称增加，每次增加2个。接地点与辅助SPOINT单元相连。同时接地点也对称分布与轮胎中心线两侧，其中一个点直接位于转向节主轴点下方。如果在一个接地点加载垂向载荷，在转向节主轴点上，不仅会出现垂向力，也会出现前后方向力，这是由于接地点耦合了轮胎的垂向模态和前后向模态。为了显示需要，使用NASTRANPLOTEL单元来代表轮胎轮廓。在建立转向节主轴点与模态自由度之间的MPC方程时，必须保证转向节主轴点是独立的，便于与整车相连。Themodaltiremodelisderivedfromthedetailednon-linearfiniteelementmodel,includingboththetireandthewheel.Byapplyingappropriatepre-load,tirepressureandotherconditions,normalmodesofadetailedfiniteelementmodelareextractedtogreaterthan200Hz.ByusingtheCraig-Bamptonmethodorothersimilarmethods,thesenormalmodesareusedtoreduceallphysicalgridsofthedetailedmodelintoalimitednumberofmodaldegreesoffreedom,modeledbyNASTRAINSPOINTs,toformamodaltiremodel.EachpairofSPOINTscorrespondstoonenormalmode.InNASTRAN,amodaltiremodelconsistsofthefollowingelements:CMASS3,CELAS3andCDAMP3spring-mass-dampersystemstorepresenteachmode,andMPCsconnectingtheSPOINTstoeachphysicalgridbeingkept.ThemodalmassCMASS3andmodalstiffnessCELAS3valuesarethedirectresultofthedynamicreductionprocess.However,themodaldampingvaluesCDAMP3areobtainedfromanexperimentalmodaltest.Forvehiclesystemanalysispurposes,onlytwosetsofthephysicalgridsneedtobekeptinthemodaltiremodel:thewheelspindlepointandthetiretogroundcontactpointsreferredaspatchpoints.Therearenormally9ormorepatchpoints.Thenumberofpatchpointsisdependentuponthelongitudinaldimensionofthecontactpatchafterthetirepreloadisapplied.Thenumberofpatchpointscanonlyincreaseinincrementsoftwosincetheyaresymmetricallylocatedaboutthetirecenterline.ThepatchpointsareconnectedtoauxiliarySPOINTs.Also,thepatchpointsarephysicallylocatedonthetirecenterlineandequallydistributedfore-aftwithonepointdirectlyunderthespindlepointatthegroundsurface.Ifaverticalinputisappliedtoonepatchpointatatime,thiscreatesnotonlyaverticalbutalsoafore-aftforcetoaconstrainedspindle,becauseofthecouplingofpatchpointstobothverticalandfore-afttiremodes.Forvisualizationpurpose,NASTRANPLOTELelementsareusedtorepresentthecarcassofatire.InformingtheNASTRANMPCequationbetweenthespindlepointandthemodaldegrees-of-freedom,thespindlepointmustbeanindependentpointintheequation,tofacilitateinterfacingofthespindlepointwiththefullvehiclesystemmodel.图3模态轮胎模型要提供四个模态轮胎。如果同一轮胎分别用于左右两个轮胎，必须小心生成输出文件。由轮胎结构决定，当生成对称的轮胎时，要使用镜像（Reflect）命令，而不是旋转（Rotate）命令。随时注意保证正确的物理特征，如接地点数和朝向。每个轮胎对应至少9个接地点，要释放垂向自由度（即NASTRAN中的节点3自由度），并要在MPC方程中体现。在NASTRAN中，质量要归一化，以用于模态质量、模态刚度和模态阻尼进行物理意义的缩放。模态轮胎最高频率要超过200Hz。转向节主轴点关联的MPC方程要包含所有轮胎模态，不要分为如下两部分（绕X旋转、绕Y旋转、绕Z旋转）（X向、Y向、Z向）。Fourmodelsshouldbeprovided–oneforeachtire.Ifasingletireismodeledforuseasboththerightandlefttires,caremustbetakenwhengeneratingtheoutputfile.Dependingonthetireconstructiondetails,itmaybenecessarytoreflectthemodelusingthevehiclecenterplaneratherthanusingrotationaboutaverticalaxis.Inanycase,correctphysicalbehavioraswellascorrectpatchpointnumberingandorientationmustbeprovided.Eachtireshouldhaveatleast9patchpointsunlessotherwiserequested.Verticaldegreesoffreedomshouldbemodeledatthepatchpoints.Thatis,degreeoffreedom3shouldbeincludedinthepatchMPCrelations.NASTRANMASSnormalizationshouldbeusedsothatthemodalmass,stiffnessanddampingarescaledinaphysicallymeaningfulmanner.Tiremodelsshouldbeprovidedatvehiclespeedsof0,30,60,80km/hourunlessotherspeedsarerequested.Theresonantfrequencyofthehighesttiremodeincludedinthemodalmodelshouldexceed200Hz.SpindleMPCequationsshouldbecoupledwithalltiremodes,notbedividedintotwosets(fore/aft,rotation,steer)(lateral,vertical,camber).假设和限制Assumptions/Limitations假设Assumptions这种建模方法假定所有组件的行为都是线性的。不模拟非线性行为。Thismethodofmodelingassumesallcomponentsbehaveinalinearfashion.Nonlinearbehaviorisnotsimulated.限制Limitations模态轮胎不包括轮胎内声腔的作用，因此无声腔的模态轮胎只用于150Hz以下分析，有声腔的模态轮胎可用于250Hz及以上分析。Oftenthemodaltiremodeldescribeddoesnotincludetheeffectsofthetireacousticcavity.Theusefulfrequencyrangewithoutanacousticcavityislimitedtoabout150Hz.Theusefulfrequencyrangewithanacousticcavitymodelcanextendto250Hzormore.载荷和边界条件Loads/BoundaryConditions无。结果Results无。性能要求PerformanceRequirements轮胎无约束模态分析：在约束接地点的所有自由度后，进行轮胎模态分析。分析结果与供应商提供的数据进行对比。Tire(Unconstrained)NormalModesAnalysis.NASTRANnormalmodesanalysisshouldbeperformedbyconstrainingthetirepatchgridsinalldegreesoffreedom.TheMPCsshouldbereferencedinthecasecontrolsection.Thenaturalfrequenciesandmodeshapesobtainedshouldbecheckedagainstthoseprovidedbysupplier.Anexampleisshownasbelow:图4轮胎模态频率图轮胎静态平衡检查：约束所有接地点自由度（SPC1~6）；转向节不约束；在转向节上加载1000N垂向力；读取接地点上反力。通过接地点反力与加载力相差不超过5%（如950N）。Tire(Constrained):StaticLoadEquilibriumCheck.Tocheckthestaticequilibriumintegrityofatiremodel,thefollowingprocedureisrecommended:Tirepatchpointsareconstrained(SPC1-6);Spindleisunconstrained;1000Nisappliedverticallydownwardsatthespindlepoint;Reactionforcesarerecoveredatthepatchpoints.Thesummationofreactionforcesatthepatchmustbewithin5%oftheappliedload,i.e.950N.分析要求ANALYSISREQUIREMENTS使用NASTRAN进行模型检查和验证NASTRANshouldbeusedformodelcheckoutandverification.参考文件DOCUMENTATION无。联系人CONTACTS无。例子EXAMPLES$************************************************************************$===========RightFrontTireModalModel==========$************************************************************************$ ModalTireModelforNASTRAN$$ TireSize: 215/65R15$$ TireConstruction: 35167AB$ WheelSize: 15x6J$ WheelType: Aluminum$ WheelOffset(mm): 15.4mm $ WheelCGOffset(mm): 0.54mm$ WheelMass(Kg): 9.5Kg$ WheelInertiaIxx(Kg-m**2):0.152Kg-m**2$ WheelInertiaIyy(Kg-m**2):0.241Kg-m**2$ WheelInertiaIzz(Kg-m**2):0.152Kg-m**2$ $ VehicleSpeed(KPH): 0.0KPH$$ TireInflationPressure(psi)30.0psi$ TireLoad(N): 4658.0N$ TireCamber(Degrees): 0.0Degrees$$ TireDeflection(mm): 22.8mm$ ModelTimeUnits: seconds(s)$ ModelLengthUnits: millimeters(mm)$ ModelMassUnits: Megagrams(Mg)$$ ModelForceUnits: Newtons(N)$ Normalization: MAX$ Highest-FrequencyMode(Hz):231.815Hz$ NumberofTirePatchPoints:9$ TirePatchPointActiveDOF:1,2,3,4$$*************************************************************************$ ValidationandCorrelation$$ Describevalidationandcorrelationofthemodelandthemethod$usedtoobtainarollingtiremodelinthislocation.)$$*************************************************************************$************************************************************************$$ ModeShapeDescriptionsandFrequencies$$Mode#FrequencyIDDescription$$14.426Y01stLateralMode$28.025X01stFore/AftMode$320.234Z01stVerticalMode$423.200W01stSteeringMode$534.534U01stBendingMode$658.739V01stTorsionalMode$765.999Y12ndLateralMode$884.127W12ndSteeringMode$984.970U12ndBendingMode$1096.773Z12ndVerticalMode$1196.460X12ndFore/AftMode$12103.195W23rdSteeringMode$13105.702Z23rdVerticalMode$1484.135V12ndTorsionalMode$15118.407X23rdFore/AftMode$16129.423U23rdBendingMode$17128.286Z34thVerticalMode$18146.706W34thSteeringMode$19142.326X34thFore/AftMode$20155.946Z45thVerticalMode$21157.044U34thBendingMode$22173.531W45thSteeringMode$23172.691X45thFore/AftMode$24189.368Z56thVerticalMode$25183.534U45thBendingMode$26192.141W56thSteeringMode$27207.130X56thFore/AftMode$28210.397U56thBendingMode$29225.098W67thSteeringMode$30231.815U67thBendingMode$$$*************************************************************************$********************************************************************$$LocalCoordinateSystem$$ PointA:GeometricCenteroftheTire$ PointB:Z-Axis,TowardsthetopofthevehiclefromPointA$ PointC:X-Axis,TowardstherearofthevehiclefromPointA$CORD2R 9500000A1A2A3B1B2B3C1C2C3$$ SpindlePoint$GRID950000095000000.00.00.0$$ TireInternalModalDOF(CouplingSpindletoModalDOF)$SPOINT9501001THRU9501999$$ TireInternalModalDOF(CouplingTirePatchPointstoModalDOF)$SPOINT9502001THRU9502999$$ ModalMassCMASS3950100195010019502001PMASS9501001.007365CMASS3950100295010029501002PMASS9501002.007310$...$$ ModalStiffness$CELAS39502001950200195010019502001PELAS950200121.16CELAS39502002950200295010029501002PELAS95020029.15$...$$ ModalDamping$CDAMP39503001950300195010019502001PDAMP9503001.0316CDAMP39503002950300295010029502002PDAMP9503002.0207$...$$*********************************************************************$$ MPCRelations-SpindletoModalDOF$$ SpindleFore/AftDeflection(X)MPC195020021-.58449095020010.00622195000000-1.095020030-.000352$...$$ SpindleLateralDeflection(Y)MPC195020022-.00662895020010-.62235395000000-1.095020030-.083250$...$$ SpindleVerticalDeflection(Z)MPC195020023-.00226795020010-.13077095000000-1.095020030.990243$...$$ SpindleCamberRotation(U)MPC195020024.00001695020010.00124795000000-1.095020030-.000006$...$$ SpindleAxisRotation(V)MPC195020025-.00119295020010.00001495000000-1.095020030-.000002$...$$ SpindleSteerRotation(W)MPC195020026-.00011495020010.00000195000000-1.095020030.000009$...$$ MPCRelations-PatchPointstoModalDOF$MPC195010010-1.095000011-.0155++95000021-.010095000031.0007++95000041.003595000051.0074++95000061.013995000071.0142++95000012-.099395000022-.2153++95000032-.255895000042-.2673++95000052-.256295000062-.2147++95000072-.097695000013-.0151++95000023-.011895000033-.0061++95000043-.005595000053-.0112+95000063-.028595000073-.0405$...$**********************************************************************$ PatchGRIDs$GRID9500001950000070.0740.84-322.710123456GRID9500002950000046.3440.83-322.710123456GRID9500003950000023.0940.89-322.710123456GRID95000049500000.0041.00-322.710123456GRID95000059500000-23.0941.11-322.710123456GRID95000069500000-46.3441.17-32