内饰车身动刚度分析规范

Q/SZJ191001-2017内饰车身动刚度分析规范SpecificationOfInputPointInertanceAnalysisAnalysisForTrimmedBody20XX20XX-09-30实施20XX-08-28发布XXXX汽车工程技术有限公司发布Q/SZXX-X-2017内饰车身动刚度分析规范范围本标准规定了术语和定义、内饰车身动刚度方法及结果处理方法。本标准适用于CAE部门的内饰车身动刚度分析。规范性引用文件无。术语和定义无。摘要Abstract动刚度是白车身性能重要的评价指标之一，其作用主要表现在车身疲劳寿命和整车舒适性上。在整车NVH分析中，振动传递路径对NVH性能有较大影响，而振动基本是从底盘通过与车身的安装接附点传递到车身，因此对接附点局部区域的动刚度进行考察特别重要，也是整车NVH分析的基础。本规范规定了动刚度分析的方法及评价标准。InputPointInertanceofBIWisoneofimportantcriteria,anditsmajorroleinthebody'sfatiguelifeandcomfort.VehicleNVHanalysis,vibrationtransmissionpathhasagreaterimpactonNVHperformanceandvibrationfromthechassiswiththeinstallationpointofthebodypassedtothebody,sodockingpointlocalareatostudytheInputPointInertanceisespeciallyimportant,andarethebasisforvehicleNVHanalysis.requirementsandEvaluationstandardfortheanalysisoftheInputPointInertance.

流程图ProcessFlowDiagram收集详细模型收集详细模型(TrimmedBody)CollectDetailedModels(TrimmedBody)设置边界条件和载荷SettheboundaryConstraintsandLoads提交计算NastranSOL111RunNastranSOL111结果后处理（HyperGraph）Resultsprocessing（HyperGraph）输出加载点加速度响应Outputaccelerationresponseatloadpoints结束End优化Optimization结果是否满足要求？IstheresultOK？YesNo评价标准Evaluationstandard图1流程图Fig1ProcessFlowDiagram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):MSC.Nastran后处理(Postprocessors):Hyperview建模和分析过程Modeling/AnalysisProcedure动刚度分析：源点导纳（InputPointInertance）分析。在一定频率范围内通过在加载点施加单位力作为输入激励，同时将该点作为响应点，测得该点在该频率范围内的加速度作为输出响应，单位为(mm/s2)/N。用于考察该点的局部动刚度。IPIanalysis:sourceadmittance(InputPointInertance)analysis.Inacertainfrequencyrangebyunitsofforceappliedattheloadpointasinputandresponsepointatthatpoint,measuredtheresponseofaccelerationasoutputintherangeoffrequenciesinunitsof(mm/S2)/N.Toinvestigatethelocalstiffnessofthepoint.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结构有限元模型是带内饰车身的TrimmedBody模型（以下简称TB模型），TB模型按照是否带副车架又分为不带副车架的TB模型和带副车架的TB模型两种。StructurefiniteelementmodelsistheTrimmed-Bodymodelswithinteriorbody(hereinafterreferredtoasTBmodel).theTBmodelcanbedividedintotwokinds,onewithasub-frameandtheotherwithoutasub-frame.副车架与车身的连接是通过衬套软连接，使用不带副车架的TB模型进行VTF分析。图2是不带副车架的VTF分析有限元模型。Onthesituationtheconnectionbetweenthesub-frameandthebodyissoft,useTBmodelwithoutasub-frametodoNTFanalysis.Thefiniteelementmodelwithoutasub-frameusedinNTFanalysisisshowinfigure2.图2不带副车架的VTF有限元模型Fig2ThefiniteelementmodelwithoutsubframeinVTF车架与车身连接是硬连接通过螺栓连接的，使用带副车架的TB模型进行VTF分析。图3是带副车架的VTF分析有限元模型。Whenthesubframeandbodyisconnectedbythehardbolts,VTFanalysisusesaTBmodelwithsub-frame.Figure3showsafiniteelementmodelwithsub-frameinVTFanalysis.图3带前后副车架的有限元模型Fig3Thefiniteelementmodelwithfrontandrearsub-frames坐标系CoordinateSystems分析采用整车坐标系,有些弹簧需要建局部坐标系。Analysisusesvehicleglobalcoordinatesystem,Localcoordinatesystemsareneededforsomespringsinthetrimmedbody.建模技巧ModelingTechniques请参阅TrimmedBodyRefertotheTrimmedBodymodelingguidelines.接附点的衬套直接用螺栓与车身侧连接时，需要建立一维CBEAM或CBAR单元螺栓模型，如摆臂接附点，见图4所示。加载点在CBEAM或CBAR单元的中点。Onthesituationthebushismodeledasaboltconnectedtothebody,a1DCBEAMelementorCBARelementcanbeusedtomodelthebolt.Forinstance,anattachmentpointattheswingarmisshowedinFigure4.TheloadingpointisatthemiddlelocationofCBEAMorCBAR.图4衬套直接用螺栓与车身侧连接的建模示意图Fig4Bushingasabolt接附点的衬套以支架总成形式与车身侧连接时，需要将固定衬套橡胶的钢圈用RBE2单元连接，钢圈中心点为RBE2主节点，钢圈上节点为RBE2从节点，RBE2单元耦合全部6个自由度。加载点在RBE2主节点，如发动左悬置接附点见图5所示。Onthecircumstancethemountingpointbushispresentedbyabracketassemblyconnectedtothebodyside,aRBE2elementshouldbeusedtomodeltherimsonthefixedbushingrubber.Theindependentnodeisthecenterofrim,andtheindependentnodesconnectthewholerim.TheRBE2coupledall6degreesoffreedoms.TheloadisimposedontheindependentnodeofRBE2.Forinstance,theleftenginemountpointisasshowninFig5.图5发动机左悬置接附点建模示意图Fig5Theleftenginemountmodeling如图6所示，为前、后减振弹簧安装支座处接附点建模方式，其加载点为前后减振弹簧支座中心点。ThemodelingmethodoffrontandreardampingspringinstallationsupportsisshowedinFigure6.Theloadingpointisthecenterpointofsprings.图6前、后减振弹簧接附点建模示意图Fig6frontandreardampingSpringsmodeling车身侧排气系统接附点的建模方式为，将被动侧挂钩与挂钩隔振器相连的区域的节点用RBE2单元与从节点连接，主节点自动生成，RBE2单元耦合全部6个自由度。加载点在RBE2单元的主节点。图7是车身侧排气系统接附点的建模示意图。Bodysideexhaustsystemmodelingmethod：TheRBE2isusedtomodelthemountingpoint,withitsdependentnodesconnectingthenodesontheregionwhichrelatedthepassivelinktothelinkisolator,whileitsindependentnodeisautomaticallygenerated.TheRBE2couplesall6degreesoffreedom.Itsindependentnodeistheloadingpoint.Figure7showsthebody-sideexhaustsystemmodeling.图7车身侧排气系统接附点建模示意图Fig7Thebody-sideexhaustsystemmodeling假设和限制Assumptions/Limitations无。载荷和边界条件Loads/BoundaryConditions约束：自由模态。Noconstraints.包括底盘悬架系统与车身相连的接附点、发动机与车身相连的接附点、副车架与车身相连的接附点、排气与车身相连的接附点。不同车型间可能因为底盘悬架系统、发动机安装方式、副车架连接和排气系统的不同，而存在差异。图8为接附点位置示意图，其中副车架、前悬、后摆臂、后减振器、后弹簧安装点、排气吊挂安装点。Includeschassissystemandvehiclebodyattachmentpoints,engineandbodyattachmentpoints,sub-frameandbodyattachmentpoints,exhaustandbodyattachmentpoints.Betweendifferentmodelsbecausethechassissuspensionsystems,engineinstallation,connectedtotheframeandexhaustsystemsofdifferent,therearedifferences.Figure8-mountpoints,subframe,frontsuspension,rearswingarm,rearshockabsorbers,rearspringmountingpoint,exhaustsuspensionattachmentpoints.图8接附点位置示意图Fig8mountpoints加载：在接附点处分别沿XYZ三个方向，加载1N随频率（20Hz~500Hz）变化的动载荷。ApplyunitloadsattheattachmentpointsinX,YandZdirectionsontheseparatesubcases.andfrequencyfrom20Hzto500Hz;加载方向和接附点的受力方向一致。接附点受力方向如果与整车坐标不一致，需要根据受力方向建立局部坐标，如摆臂接附点。图9是局部坐标、整车坐标示意图。Applytheloadintheattachmentpointsforceddirection.Iftheloadingdirectionisinconsistentwiththeglobalcoordinatesystem,thelocalcoordinatesystemisneeded.anattachmentpointattheswingarmisshowedinFigure8.Figure8showsthelocalandglobalcoordinatesystems.图9局部坐标、整车坐标示意图Fig9Thelocalcoordinatesystemandtheglobalcoordinatesystem载荷大小：单位载荷1N。Load:unitload1N模态阻尼：1-20Hz是0.1，20－500Hz是0.04；Modaldamping:1-20Hzwas0.1,20-500Hzwas0.04;载荷激励频率范围：2Hz－200Hz；Loadexcitationfrequencyrange:50Hz－500Hz；结构模态频率范围：0Hz－500Hz；Structuralmodalfrequencyrange:0Hz－500Hz求解采用NASTRAN模态频率响应SOL111。Solver111具体的参数设置详见15.例子Specificparametersettingsisshowninchapter15EXAMPLES.结果Results输出加载点加速度响应，加速度曲线通过以下三种积分方法得到等效动刚度值：Outputaccelerationresponseatloadpoints,accelerationcurvesthroughthefollowingthreekindsofintegrationmethodforequivalentstiffnessvalues：Kd_Method分为三类：Area_Ratio:加速度的面积与单位动刚度的面积比值来获取Kd值。Area_Ratio:：AccelerationunitsofareaandthearearatioofdynamicstiffnesstoobtainKdvalues.Disp_Average,：采用加速度换算成位移，然后取位移的倒数获取Kd值。Disp_Average：Convertaccelerationdisplacement,andthentakethereciprocalofthedisplacementtoobtainKdvalues.Disp_log_Average：采用加速度换算成位移的Log值再换算成真实位移取倒数获取Kd值。Disp_log_Average：ConvertaccelerationdisplacementLogvalueisthenconvertedtotherealcountdownGetstheKdvaluedisplacement.图10IPI分析结果Fig10IPIAnalysisofresults性能要求PerformanceRequirements等效动刚度曲线在目标值曲线之下且Kd值大于目标动刚度值，该接附点在该方向的动刚度满足目标值。反之不满足。EquivalentstiffnesscurveintargetvalueunderthecurveanddynamicstiffnessvaluesofKdvalueisgreaterthanthetarget,whichpointsinthedirectionofdynamicstiffnessontargetvalues.Otherwisedonotmeet.根据接附点受力方向，可分为主方向和次方向。主方向目标值为10000N/mm，次方向目标值为7000N/mm。针对不同车型定位不同，目标值可根据具体项目要求进行调整。Accordingtothestressdirection,canbedividedintoprimaryandsecondarydirections.Primarydirectionoftargetvaluesforthe10000N/mmanddirectionoftargetvaluesfor7000N/mm.Thetargetvaluecanbeadjustedaccordingtothespecificprojectrequirements.分析要求ANALYSISREQUIREMENTS参考文件DOCUMENTATION无。联系人CONTACTS无。例子EXAMPLES$SOL111CEND$$$$$CaseControlCards$$$$$$AUTOSPC(NOPRINT)=YESECHO=NONEMETHOD(STRUCTURE)=10FREQ=30SDAMPING=40$==============================================================================$$NODESETLABELFOROUTPUT$$SET1=1010$$$$$SubcasesList$$$SubcaseFLT