副车架刚度分析规范

Q/SZJ191001-2017副车架刚度分析规范SpecificationOfStiffnessAnalysisForCradleSub-frame20XX20XX-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副车架刚度分析规范范围本标准规定了前后副车架刚度分析的分析方法。本标准适用于CAE部门前后副车架刚度分析。规范性引用文件无。术语和定义无。摘要Abstract分析规范主要针对前后副车架。Thisprocedureoutlinesananalyticaltechniqueforevaluatingthestiffnessofenginecradlesandrearsub-frames.流程图组建详细模型组建详细模型Collectdetailedmodel(s)求解Solve加载Applyconstraintsandloads输出位移并计算Outputdisplacementandcompute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):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模型包含前副车架或者后副车架，也可能包括零长度的弹簧单元。Themodelshouldincludeafiniteelementrepresentationoftheenginecradleorrearsub-frame.Zero-lengthspringelementsmayalsoberequired.图2前后副车架模型坐标系CoordinateSystems整车坐标系Globalcoordinatesystem建模技巧ModelingTechniques无。假设和限制Assumptions/Limitations本规范仅用于静态线性分析Theprocedureisapplicableonlytostaticlinearanalysis.载荷和边界条件Loads/BoundaryConditions约束Constraints针对如下三种模型状态，进行不同约束处理方式：副车架与车身连接对于软连接:在副车架与车身的安装孔中心位置建立一个零长度的弹簧单元代表此处车身刚度；每个自由度对应一个弹簧单元；弹簧单元一端与副车架相连，一端接地。用RBE3或者类似单元来连接弹簧单元与副车架。对于硬连接:如果有安装点处局部刚度可用，可采用软连接的处理方式。如果无局部刚度信息，则在安装点处直接接地约束。副车架包含在车身或带内饰车身模型中，则软连接或硬连接的分析方法都可以使用，但如果局部车身刚度无，则优先使用硬连接的分析方法。自由状态对于软连接:计算副车架与车身连接点刚度，使用惯性释放的方法。对于硬连接:不推荐使用该方法Themodelcanbeconstrainedinoneofthreeways:CradletogroundatbodyattachmentpointsForisolatedcradle.Attachcradletogroundatmountcentersthroughzero-lengthonedegree-of-freedomspringelementsrepresentingelastomerbodymounts.Onespringforeachdegreeoffreedom.Attachoneendtostructure;attachotherendtoground.RBE3(orequivalentelement)isthepreferredmethodtoattachspringstostructure.Forhardmountedcradle.Iflocalbodystiffnessinformationisavailable,methodissimilartothatforisolatedcradledescribedabove.Ifnolocalbodystiffnessinformationisavailable,attachtogroundatbodyattachmentpointsintranslationaldegreesoffreedomonly.Cradletoportionofbodystructureorfulltrimmedbody.Thismethodcanbeusedforeitherisolatedorhard-mountedstructures,andisthepreferredmethodofconstraintforhard-mountedcradlesiflocalizedbodystiffnessvaluesarenotavailable.Noconstraints(free-free)Forisolatedcradle.RequiredconstraintforInertialStiffnesscalculationsatcradlesideofcradletobodyinterfacelocations.Forhard-mountedcradle.Notrecommended.载荷Loads在副车架上悬架/转向/动力的安装点处加载单位力Individualunitloadsappliedateachsuspension/steering/powertraininterfaceareusedtodeterminestaticstiffness.结果Results无。性能要求PerformanceRequirements副车架上安装点静刚度目标值一般10倍于衬套静刚度。惯性释放的方法计算副车架与车身软连接时的安装点刚度，或者在带内饰车身（包含副车架）状态下硬连接时的安装点刚度。使用PARAM,INREL,-2，无SUPPORT或SUPPORT1的方法来进行计算。Agoodruleofthumbstaticstiffnesstargetis10timesthestaticbushingrate.Forinertialstiffness(alsoknownasfree-freestiffnessorzeroHzstiffness)isatechniqueusedtoquantifyingthestiffnessatthecradletobodyinterfaceofanisolatedcradleorsub-frame,oroftheentirecradle/trimmedbodyinthecaseofahard-mountedcradle.