Q/SZJ191001-2017副車架剛度分析規(guī)范SpecificationOfStiffnessAnalysisForCradleSub-frame20XX20XX-09-30實施20XX-08-28發(fā)布XXXX汽車工程技術(shù)有限公司發(fā)布Q/SZXX-X-2017副車架剛度分析規(guī)范范圍本標(biāo)準(zhǔn)規(guī)定了前后副車架剛度分析的分析方法。本標(biāo)準(zhǔn)適用于CAE部門前后副車架剛度分析。規(guī)范性引用文件無。術(shù)語和定義無。摘要Abstract分析規(guī)范主要針對前后副車架。Thisprocedureoutlinesananalyticaltechniqueforevaluatingthestiffnessofenginecradlesandrearsub-frames.流程圖組建詳細(xì)模型組建詳細(xì)模型Collectdetailedmodel(s)求解Solve加載Applyconstraintsandloads輸出位移并計算Outputdisplacementandcompute圖1流程圖Fig1ProcessFlowDiagram工具描述ToolDescription仿真分析過程中需要用到的如下軟件:Thefollowingsoftwarefacilitatestheanalyticalsimulationprocess:前處理(Preprocessors):Hypermesh求解器(AnalysisCode):Nastran后處理(Postprocessors):HyperView建模和分析過程Modeling/AnalysisProcedure單位Units分析中所用單位制如下所示:Theunitsusedintheanalysisareasfollows:力(Force) 牛頓(N)質(zhì)量(Mass) 噸(Ton)長度(Length) 毫米(mm)時間(Time) 秒(Second)內(nèi)容Contents模型包含前副車架或者后副車架，也可能包括零長度的彈簧單元。Themodelshouldincludeafiniteelementrepresentationoftheenginecradleorrearsub-frame.Zero-lengthspringelementsmayalsoberequired.圖2前后副車架模型坐標(biāo)系CoordinateSystems整車坐標(biāo)系Globalcoordinatesystem建模技巧ModelingTechniques無。假設(shè)和限制Assumptions/Limitations本規(guī)范僅用于靜態(tài)線性分析Theprocedureisapplicableonlytostaticlinearanalysis.載荷和邊界條件Loads/BoundaryConditions約束Constraints針對如下三種模型狀態(tài)，進(jìn)行不同約束處理方式：副車架與車身連接對于軟連接:在副車架與車身的安裝孔中心位置建立一個零長度的彈簧單元代表此處車身剛度；每個自由度對應(yīng)一個彈簧單元；彈簧單元一端與副車架相連，一端接地。用RBE3或者類似單元來連接彈簧單元與副車架。對于硬連接:如果有安裝點處局部剛度可用，可采用軟連接的處理方式。如果無局部剛度信息，則在安裝點處直接接地約束。副車架包含在車身或帶內(nèi)飾車身模型中，則軟連接或硬連接的分析方法都可以使用，但如果局部車身剛度無，則優(yōu)先使用硬連接的分析方法。自由狀態(tài)對于軟連接:計算副車架與車身連接點剛度，使用慣性釋放的方法。對于硬連接:不推薦使用該方法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.載荷Loads在副車架上懸架/轉(zhuǎn)向/動力的安裝點處加載單位力Individualunitloadsappliedateachsuspension/steering/powertraininterfaceareusedtodeterminestaticstiffness.結(jié)果Results無。性能要求PerformanceRequirements副車架上安裝點靜剛度目標(biāo)值一般10倍于襯套靜剛度。慣性釋放的方法計算副車架與車身軟連接時的安裝點剛度，或者在帶內(nèi)飾車身（包含副車架）狀態(tài)下硬連接時的安裝點剛度。使用PARAM,INREL,-2，無SUPPORT或SUPPORT1的方法來進(jìn)行計算。Agoodruleofthumbstaticstiffnesstargetis10timesthestaticbushingrate.Forinertialstiffness(alsoknownasfree-freestiffnessorzeroHzstiffness)isatechniqueusedtoquantifyingthestiffnessatthecradletobodyinterfaceofanisolatedcradleorsub-frame,oroftheentirecradle/trimmedbodyinthecaseofahard-mountedcradle.