NVH动力总成建模规范

Q/SZJ191001-2017NVH动力总成建模规范ModelingSpecificationOfPowertrainforNVH201XX201XX-XX-XX发布20XX-XX-XX实施XXXX汽车工程技术有限公司发布Q/SZXX-X-2017NVH动力总成建模规范范围本标准规定了NVH动力总成建模方法。本标准适用于CAE部门动力总成NVH模型建模。规范性引用文件无。术语和定义无。摘要Abstract动力总成子系统包括电机,减速器,电机悬置,减速器悬置，油冷器以及其他附件比如空调压缩机等。根据分析的现象和感兴趣的频率范围,动力总成可以采用三种不同的方式进行建模:刚体模型、带有传动齿轮机构的刚体模型和详细的柔性模型。Thepowertrainsubsystemconsistsofthemotor,transmission,motormounts,transmissionmounts,motoroilandanyotheraccessoriesdirectlyattachedtothemotorsuchasACcompressor,etc.Dependingonthephenomenonbeinganalyzedandfrequencyrangeofinterest,thepowertraincanbemodeledinthreedifferentways:rigidbodymodel,rigidbodymodelwithtransmissiongearmechanism,anddetailedflexiblemodel.刚性动力总成模型将整个动力总成子系统看成是单一刚性质量和转动惯量。每个动力总成悬置是模拟三个平动弹簧单元。该模型易于构建,需要很少的计算机资源来运行。它适用于低频范围(0-50Hz)的振动研究,如动力总成的刚体模式、车粗糙路震动、动力总成悬置优化等。对于其他低频(0-50Hz)振动研究,如瞬态响应(如juggle),动力总成子系统仍可模拟为刚体模型。但是,为了得到正确的扭转传动系统共振,必须包括传动齿轮机构。Therigidpowertrainmodeltreatsthewholepowertrainsubsystemasonesinglerigidmassandmassmomentofinertia.Eachpowertrainmountissimulatedwiththreetranslationalspringelements.Thismodeliseasytobuildandneedsfewcomputerresourcestorun.Itissuitableforlowfrequencyrange(0-50Hz)vibrationstudies,suchaspowertrainrigid-bodynormalmodes,vehicleroughroadshakes,powertrainmountoptimizationforroughroadshakes,etc.Forotherlowfrequency(0-50Hz)vibrationstudies,suchastransientresponsessuchasjuggle,thepowertrainsubsystemcanstillbesimulatedasarigidbodymodel.However,thetransmissiongearmechanismmustbeincludedinordertoobtainthecorrecttorsionaldrivelineresonance.更高的频率关注范围高达100Hz,如车辆结构承担动力总成噪音,应使用详细的r柔性的动力总成模型模拟。当采用模态频率响应法求解此类问题时,应保留150Hz-200Hz的模态,以限制模态截断所造成的误差。因此,刚性动力总成模型可能不再适用,因为典型的动力总成第一弯曲/扭转模式开始在70Hz的纵向安装动力总成。(对于横向安装的动力总成,第一弯曲模式通常是大140Hz。因此,刚性block模型可用于更高的频率。动力总成通常是使用实体单元和壳单元的组合来建模。创建模型很困难,需要大量的计算资源才能运行。处理动力总成在一个完整的车辆系统分析可能需要加速技术。Higherfrequencyrangeconcerns,upto100Hz,suchasvehiclestructural-bornepowertrainnoise,shouldbesimulatedusingadetailedflexiblepowertrainmodel.Whenthemodalfrequencyresponsemethodisusedtosolvethistypeofproblem,thenormalmodesupto150Hz-200Hzforeachcomponentofthesystemshouldberetainedinordertolimittheerrorscausedbymodaltruncation.Therefore,arigidpowertrainmodelmaynolongerbesuitablebecausetypicallythepowertrainfirstflexuralbending/torsionmodestartsatabout70Hzforalongitudinalmountedpowertrain.(Foratransversemountedpowertrain,thefirstflexuralmodeisusuallyaround140Hz.Therefore,therigidblockmodelcanbeusedtoamuchhigherfrequency.)Thepowertrainisusuallymodeledusingacombinationofsolidelementsandshellelements.Itisdifficulttocreatethemodelandrequiresalargeamountofcomputingresourcestorun.Thesuperelement/CMStechniquemaybeneededtoprocessthepowertraininafullvehiclesystemanalysis.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模型包含白车身、翼子板、加强件、螺栓连接的横梁、螺栓连接的副车架、前后风窗玻璃、CCB等。Body-in-whitewith:fenders,reinforcingcomponents,boltedcrossmembers,withsub-frameifrigidly(bolted)connected,withandw/owindshield,CCB(crosscarbeam).坐标系CoordinateSystems在建立动力总成模型时,坐标系是极其重要的。为了正确定义传动系统,需要三个坐标系。主坐标系和动力总成坐标都应参照SAE坐标系建立。如果这点正确完成的,只有SAE坐标需要重新定义,用以以改变的位置动力总成位置。Coordinatesystemsareextremelyimportantinbuildingapowertrainmodel.Threecoordinatesystemsareneededinordertodefinethepowertraincorrectly.BoththeprincipalandpowertraincoordinatesshouldbebuiltreferencingtheSAEcoordinates.Ifthisisdonecorrectly,onlytheSAEcoordinatesneedtoberedefinedtochangethelocationofthepowertrain.SAE坐标系SAECoordinates这个坐标系必须被定义,因为动力总成转动惯量在这个坐标系在定义。在这个坐标系中,原点位于曲轴后端的的机体中心,Z轴是指向下(相对于整车Z),而X轴指向块的曲轴前端的的机体中心。其他两个坐标系是参考这个坐标系建立。为了建立这个坐标系,将原点设置为曲轴后端的的机体中心。对于横向安装动力总成从原点的Z坐标减去100来定义坐标系Z轴,从原点的Y坐标增加100来定义坐标系X轴。对于纵向动力总成,Z轴的定义是相同的,但是,X轴是通过从原点的X坐标减去100来定义的。这一切都应该在CORD2R卡片上完成。如果有一个倾斜的动力总成,这需要理解在这一点上,是需要移动Z轴和X轴的。Thiscoordinatesystemmustbedefinedbecausethepowertraininertiasareputtogetherinthiscoordinatesystem.Inthissystemtheoriginisatthecenterofthecrankrearfaceofblock,thezaxisispointeddownward(oppositevehiclez),andthex-axisispointedtowardthecenterofcrankfrontfaceofblock.Theothertwocoordinatesystemsarebuiltreferencingthisone.Tobuildthiscoordinatesystem,settheorigintotherearfaceofblockcenterofcrank.Foratransversemountedpowertrainsubtract100fromthez-coordinateoftheorigintodefinethezaxis,andadd100tothey-coordinateoftheorigintodefinethex-axis.Foralongitudinalpowertrain,thez-axisisdefinedthesame,however,thex-axisisdefinedbysubtracting100fromthex-coordinateoftheorigin.ThisshouldallbedoneonaCORD2Rcardinvehiclecoordinates.Ifthereisatilttothepowertrain,thisneedstobecomprehendedatthispointbymovingthezandxaxesasneeded.动力总成坐标系PowertrainCoordinates动力总成坐标是特定于动力总成的坐标。所有动力总成网格都应该定义在此坐标系中,并在此坐标系下进行分析。所有动力总成载荷都应在此坐标系下定义。唯一的例外是那些需要局部坐标系的网格，这些包括弹簧和齿轮力矩臂。但是,这些局部坐标系应根据动力总成坐标系来定义。唯一允许偏离的节点是质心。质心应该在SAE坐标中定义,因为它是公司数据库中质心数据的坐标系统。但它也应该在动力总成坐标中进行分析。Thepowertraincoordinatesarecoordinatesspecifictothepowertrain.Allpowertraingridsshouldbedefinedinthiscoordinatesystem,andanalyzedinthiscoordinatesystem.Allloadsshouldbeappliedtothepowertraininthiscoordinatesystemforconsistency.Theonlyexceptionsarethosegridswhichrequirealocalcoordinatesystem.Theseincludesprings,andgearmomentarms.However,thoselocalcoordinatesystemsshouldbedefinedintermsofthepowertraincoordinatesystem.Theonlygridallowedtodeviatefromthisisthecenterofgravitygrid.ThisshouldbedefinedintheSAEcoordinates,becauseitisthecoordinatesystemoftheCGdataonthecorporatedatabase.Ittooshouldbeanalyzedinthepowertraincoordinates.要构建此坐标系,请将原点定义为SAE坐标系统的原点。将SAE坐标的Z向-100设置为Z轴，SAE坐标的X向+100设置为X轴。这应该是在SAE坐标中的CORD2R卡片上完成的。Tobuildthiscoordinatesystem,definetheorigintobetheoriginoftheSAEcoordinatesystem.Setthez-axistobe–100inthez-directionofSAEcoordinates.Setthex-axisto100inthexdirectionofSAEcoordinates.ThisshouldbedoneonaCORD2RcardintheSAEcoordinates.主坐标系PrincipalCoordinates主坐标是动力总成惯性矩阵的主轴。该坐标系是在SAE坐标系中定义的。惯性数据的企业数据库是一致的。要建立这个坐标系,将原点设定为动力总成的质心。将第三个主轴方向余弦到原点定义为Z轴。将第一个主轴方向余弦到原点定义为X轴。这应该是在SAE坐标中的CORD2R卡片上完成的。Theprincipalcoordinatesaretheprincipalaxesoftheinertiamatrixofthepowertrain.ThiscoordinatesystemisdefinedintheSAEcoordinatesystem.Thisistobeconsistentwiththecorporatedatabaseofinertiadata.Tobuildthiscoordinatesystem,settheorigintotheCGofthepowertrain.Addthethirdprincipalaxisdirectioncosinestotheorigintodefinethez-axis.Addthefirstprincipalaxisdirectioncosinestotheoriginforthex-axis.ThisallshouldbedoneinSAEcoordinatesonaCORD2Rcard.建模技巧ModelingTechniques刚性动力总成模型RigidPowertrainModel一个典型的刚性动力总成模型如图1所示。它由表示电机/减速器的结构/附件的CONM2/RBE2单元组成。带PELAS属性的CELAS2或CELAS1单元表示电机悬置,PLOTEL单元表示动力总成几何外形。AtypicalrigidpowertrainmodelisshowninFigure1.ItconsistsofCONM2/RBE2elementsforthemotor/transmissionstructure/accessories,CELAS2orCELAS1withPELASelementsformotormounts,andPLOTELelementsforgeometryrepresentationofthepowertrain.图1刚性动力总成模型要创建刚性动力总成模型,需要以下信息:曲轴后端的的机体中心位置;电机w.r.t.车辆坐标系的方向;在曲轴的前轴承和后轴承之间的一个点的位置;前、后曲轴轴承和输出轴轴承的位置;电机和减速器的几何形状,以便为动力总成的粗略轮廓提供视觉显示;动力总成的质量,转动惯量和质心位置和主惯量余弦方向。Thefollowinginformationisneededtocreatearigidpowertrainmodel:motorrear-face-of-block-crankshaftpointlocationw.r.t.thevehicle;orientationofthemotorw.r.t.thevehiclecoordinatesystem;locationofapointonthecrankshafthalfwaybetweenthefrontandrearbearings;locationsofthefrontandrearcrankshaftbearingsandtheoutputshaftbearings;geometryofmotorandtransmissioninordertocreatearoughoutlineofthepowertrainforvisualdisplays;mass,inertia,andc.g.locationanddirectioncosinesfortheprincipalinertiaforthepowertrain.在质心上创建一个CONM2单元,以表示动力总成质量和转动惯量。RBE2单元将动力总成的质心连接到以下各点:电机和变速箱悬置、输出轴轴承和几何显示点。ACONM2elementiscreatedatthec.g.torepresentthepowertrainmassandmassmomentofinertia.AnRBE2elementconnectsthec.g.ofthepowertraintoeachofthefollowingpoints:motorandtransmissionmounts,outputshaftbearing,andgeometrydisplaypoints.转动惯量MassmomentsofInertia对于大多数类型的电机和减速箱,他们的质心,质量,转动惯量和方向余弦可以在在噪声和振动测试中得到。用户应验证表中的测试样本附件对模拟的动力总成硬件。如果测试数据中未包括任何附件,则应添加其质量和转动惯量。Formosttypesofmotorandtransmissions,theirc.g.,mass,inertia,anddirectioncosinescanbeobtainedfromNoiseandVibrationtest.Theusershouldverifythetestspecimenaccessoriesinthetableagainstthepowertrainhardwarebeingsimulated.Ifanyaccessoryisnotincludedinthetestdata,itsmassandmomentofinertiashouldbeadded.对于坐标系，需要特别小心。Particularcareisrequiredwithrespecttothecoordinatesystems.动力总成惯性试验数据是指SAE坐标系,它与车辆坐标系不一样。要定义电机的质量和惯性属性,需要定义一个坐标系,该坐标系统与主坐标（4.3.3节）相同。动力总成转动惯量的CONM2卡应该写在这个主坐标系中。ThepowertraininertiatestdatareferstotheSAEcoordinatesystem,whichisnotthesameasthevehiclecoordinatesystem.Todefinethemassandinertiapropertiesofthemotor,acoordinatesystemneedstobedefinedthatisthesameastheprincipalcoordinates(section4.3.3).TheCONM2cardfortheinertiaofthepowertrainshouldbewritteninthisprincipalcoordinatesystem.增加惯量AddingInertias惯性矩阵包括3个主惯性矩和惯性积。请注意,矩阵是真正的对称的。Theinertiamatrixincludesthethreemomentsofinertia,andtheproductsofinertia.Notethatthematrixisrealsymmetric.主惯性是该矩阵的特征值,主轴是特征向量。这会导致SAE坐标中的矩阵I与主惯性之间的关系。Theprincipalinertiasaretheeigenvaluesofthatmatrix,andtheprincipalaxesaretheeigenvectors.ThisresultsinarelationshipbetweenamatrixIintheSAEcoordinates,andtheprincipalinertias.元素a是主轴和X轴之间夹角的余弦值。元素b是主轴和Y轴之间夹角的余弦值,元素c是主轴和Z周之间夹角的余弦值。下标1、2和3指定第一、第二和第三个主要组件。惯性数据库中给出的所有数据都被引用到了质心。要将质心参考惯性矩阵转换为参照不同点的惯性矩阵,首先将主惯性矩转换为动力总成坐标。然后应用以下公式。Theelementaisthecosineoftheanglebetweentheprincipalaxis,andthex-axis.Theelementbisthecosineoftheanglebetweentheprincipalaxisandthey-axis,andtheelementcisthecosineoftheanglebetweentheprincipalaxisandthez-axis.Thesubscripts1,2,and3designatethefirst,second,andthirdprincipalcomponents.Allofthedatagivenintheinertiadatabaseisreferencedtothecenterofgravity.Totranslatefromacgreferencedinertiamatrixtoaninertiamatrixreferencedtoadifferentpoint,firsttransformtheprincipalinertiastothepowertraincoordinates.Thenapplythefollowingformulas.其中x、y和z是从质心到新的参考位置的x、y和z距离,m是零件的质量,素数表示惯性在不同于质心的参考。为了增加电机惯量和变速箱惯量,首先通过两个质量相加来计算总质量。然后计算新的质心。Wherex,y,andzarethex,y,andzdistancesfromthecgtothenewreferencelocation,misthemassofthepart,andtheprimeindicatestheinertiasatareferencedifferentfromthecg.Inordertoaddthemotorinertiaandthetransmissioninertia,firstcalculatethetotalmassbyaddingthetwomasses.Thencalculatethenewcg.使用这些新的质心坐标作为x、y和z的方程式来转换电机和变速器的惯性参照值。然后简单地将两个新的惯性矩阵相加。解决了该程序集的特征值问题,以确定主惯性和轴。Usethesenewcgcoordinatesasthex,y,andzintheequations(4.4.1.1.1-3)totransforminertiareferencesforbothmotorandtransmission.Thensimplyaddthetwonewinertiamatricestogether.Solvetheeigenvalueproblemofthisassemblytodeterminetheprincipalinertiasandaxes(equation4.4.1.1.1-2)电机/减速器悬置Motor/TransmissionMounts有两种类型的悬置目前用于汽车设计:常规橡胶安装和液压安装。它们在NVH分析中用不同方法模拟。Therearetwotypesofmountscurrentlyusedinautomotivedesign:conventionalrubbermountandhydraulicmount.TheyaresimulateddifferentlyforNVHanalysis.橡胶悬置使用零长度弹簧元件带PELAS的CELAS2或CELAS1。在弹簧的两侧各放一个一半质量的CONM2单元。在压缩和剪切方向上获得了悬置刚度和阻尼率。如果安装方向与车辆系统的全局坐标系不一致,则必须使用局部坐标系(CORD2R)。Rubbermountsaremodeledusingzero-lengthspringelementCELAS2orCELAS1withPELAS.HalfofthemountmassshouldbeplacedoneachsideofthespringsusingCONM2elements.Mountstiffnessanddampingratesareobtainedincompressionandsheardirections.Ifmountorientationsarenotalignedwithglobalcoordinateofthevehiclesystem,localcoordinates(CORD2R)mustbeused.除了橡胶材料和悬置设计,悬置刚度/阻尼和比率还取决于许多其他环境因素,如车辆的预载、频率范围、位移幅值、温度等。因此,在请求装入速率测试数据时,重要的是在什么条件下(预载、频率、温度、峰振幅)指定和理解安装速率。对于相同的悬置设计,不同应用的模型模拟中可能需要不同的安装速率/比率,如平滑的路面震动与粗糙的路面震动,或者打开的节流条件。Besidestherubbermaterialsandmountdesignconstruction,themountstiffness/dampingrateandratioalsodependonmanyotherenvironmentalfactors,suchaspre-load,frequencyrange,anddisplacementamplitudeofmountinvehicle,temperature,etc.Therefore,whenrequestingmountratetestdata,itisimportanttospecifyandunderstandunderwhatconditions(pre-load,frequency,temperature,peak-to-peakamplitude)themountratesareobtained.Forthesamemountdesign,differentmountrate/ratiomaybeneededinthemodelsimulationfordifferentapplication,suchassmoothroadshakevs.roughroadshake,orwideopenthrottleconditions.对于液压悬置,应使用多阻尼器模型来准确地表示其动态特性。J.Hicks开发的一个叫HMGEN的fortran程序可以自动创建多阻尼器模型从动态模量或传递测量。Forhydraulicmounts,amulti-spring-dampermodelshouldbeusedtoaccuratelyrepresentitsdynamicbehavior.AFORTRANprogramcalledHMGENdevelopedbyJ.Hicksisavailabletoautomaticallycreatethemulti-spring-dampermodelfromthedynamicmodulusortransmissibilitymeasurements.显示单元DisplayElements创建PLOTEL单元来显示动力总成的轮廓。它们不会给模型增加任何刚度或质量。他们应该根据动力总成几何变动来更新。在研究动力总成刚体模态形状时,一个过时的PLOTEL模型可能会产生误导,特别是在耦合模态时。PLOTELelementsarecreatedtoshowtheoutlineofthepowertrain.Theydonotaddanystiffnessormasstothemodel.Theyshouldbeupdatedaccordingtothepowertraingeometry.Anout-of-datePLOTELmaybemisleadingwhenstudyingpowertrainrigid-bodymodalshapes,especiallyifthemodeiscoupled.MTDES程序MTDESProgram交互式程序允许用户能够快速、方便地构建nastran模型。各种图形用户面板用于输入动力总成的位置和坐标系,安装位置和属性,并选择从各种动力总成轮廓。该程序已经建成了它的惯性数据库,上面提到的能力,方便地结合各种惯性组件在一起。该程序可以处理液压悬置模型以及静态和动态率的悬置。传输模型也建立了与建立在动力学为各种各样的齿轮比率为一些概要模型,虽然之后用户将必须根据他的具体比率修改nastran文件。TheinteractiveprogramallowsausertobeabletobuildaNASTRANmodelveryquicklyandeasily.Variousgraphicaluserpanelsareusedtoinputthepowertrainlocationandcoordinatesystem,mountlocationsandproperties,andtoselectfromavarietyofpowertrainoutlines.Theprogramhasbuiltintoittheinertiadatabasementionedabovealongwiththecapabilityofeasilycombiningvariousinertiacomponentstogether.Theprogramcanhandlethehydraulicmountmodelaswellasstaticanddynamicratesforthemounts.Thetransmissionmodelsarealsosetupwiththebuiltindynamicsforthevariousgearsratiosforsomeoftheoutlinemodels,althoughtheuserwillhavetomodifytheNASTRANdecklaterforhisspecificsetofratios.该程序允许用户通过各种不同类型的分析检查出动力总成的接地模型。分析包括:模态、地面响应、频率响应、视质量、静态线性和非线性分析。优化和变形分析也可以与前面提到的每种类型的分析一样执行。应该指出的是,这些分析是运行的电机安装到地面。在这种情况下,动力总成的模态可以比在整车中的动力总成模态高2-5Hz以上,。MTDES应该在程序中非常早期使用,以帮助定义安装位置。它的优化程序可以用来获得最佳安装位置的竞争目标,如动力总成运动控制与最小化的粗糙的道路震动。Theprogramallowstheusertocheckoutthepowertraintogroundmodelthroughavarietyofdifferenttypesofanalyses.Theanalysesinclude:modal,groundresponse,frequencyresponse,apparentmass,staticlinearandnonlinearanalysis.Optimizationandvariationalanalysiscanalsobeperformedwitheachofthepreviousmentionedtypesofanalysis.Itshouldbenotedthattheseanalysesarerunwiththemotormountedtoground.Inthiscondition,themodesofthepowertraincanbeasmuchas2-5Hzhigherthanthemodesofthepowertraininthevehicle.MTDESshouldespeciallybeusedveryearlyinaprogramtohelpdefinemountlocations.Itsoptimizationprogramscanbeusedtoobtainthebestmountlocationforcompetingobjectivessuchaspowertrainmotioncontrolversusminimizingidleshakeorroughroadshake.一旦验证了模型,可以使用公司编号方案创建动力总成模型的nastran文件。nastran文件还将包括电机和变速箱轮廓,所有的sol200卡的持续电机安装优化,和传动齿轮系统的机制如下所述。nastran文件上的每个安装将包括三额外的网格点,用于定义悬置的优化方向。该模型还将包含与半轴连接的点。Oncethemodelisverified,aNASTRANdeckofthepowertrainmodelcanbecreatedusingthecorporatenumberingscheme.TheNASTRANdeckwillalsoincludethemotorandtransmissionoutlines,alltheSOL200cardsforcontinuingmotormountingoptimization,andthetransmissiongearsystemmechanismmentionedbelow.EachmountintheNASTRANdeckwillincludethreeextragridpointsthatareusedtodefinethemountorientationforoptimizationinFASTAR.Themodelwillalsocontainthepointsfortheconnectionofthedriveaxles.nastran文件也一个简单的动力-弯曲模型的开发。电机和传动部件被连接在一起,在后面的block与6自由度弹簧系统,可以调节弯曲模态。TheNASTRANdeckisalsosetupsothatasimplepowertrain-bendingmodelcanbedeveloped.Themotorandtransmissionpartsarehookedtogetherattherearfaceofblockwitha6-dofspringsystemthatcanbetunedtotheestimatedbendingmodesofthesystem.带减速器的刚体动力总成模型RigidPowertrainmodelwithTransmissionMechanism动力总成的模型类似于4.4.1.1节所述,除了变速器的旋转部件。图2显示传动系有限元的传输部分.集中质量(CONM2's)代表减速器齿轮、U型接头以及传动系统中的其它离散质量。对此建模的关键是电机往复质量的转动惯量。此信息必须从动力总成部门,并放置在曲轴中心线和机体后端面的一个单独的CONM2。这种转动惯量是半轴模态的重要部分。ThepowertrainismodeledsimilarlyasstatedinSect.4.4.1.1exceptfortherotationalcomponentsofthetransmission.Figure2showsthetransmissionportionofthedrivelineFEM.Concentratedmasses(CONM2’s)representthetransmissiongears,U-joints,andotherdiscretemassesinthedriveline.Criticaltothismodelingistherotaryinertiaofthereciprocatingmassofthemotor.ThisinformationmustbeobtainedfromthepowertraingroupandplacedasaseparateCONM2onthecrankshaftcenterlineandtherear-face-of-block.Thisinertiaplaysanimportantpartisthedrivelinemodes.图2减速器有限元网格模型轴承Bearings轴承是用来支持减速器组件的旋转。他们通常是一个主点在动力总成质心，从点在实际轴承位置的RBE2。所有自由度,除了部件旋转的那一个,都是在RBE2卡上定义的。这种自由度,在动力总成的坐标系下,通常是4自由度。Bearingsareusedtosupporttherotatingcomponentsofthetransmission.TheyareusuallyanRBE2withtheindependentnodeattheCGofthepowertrain,andthedependentnodeattheactualbearinglocation.Alldegreesoffreedom,excepttheonewhichthepartrotatesaboutaredefinedontheRBE2card.Thisdegreeoffreedom,inpowertraincoordinates,istypicallythe4DOF.链轮ChainSprocket设计Design很多减速器都有一条链和两个链轮，将动力从一个曲轴传到另一个平行曲轴。Manytransmissionshaveachainandtwosprocketsthattransferpowerfromthecrankaxistoanaxisparalleltothecrank.组成Include需要每个链轮的转动惯性以及链轮和链条的质量,。通常,CONM2卡用于质量和转动惯量。到每个链轮的质量中都要添加一半链的质量。Therotationalinertiaofeachofthesprocketsisneeded,aswellasthemassofthesprocketsandthechain.Typically,aCONM2cardisusedforthemassandrotationalinertia.Halfofthechainmassisoftenaddedtothemassofeachsprocket.表示链轮半径的力矩臂应使用Amomentarmrepresentingtheradiusofthesprocketshouldbeused.该链通常用刚度弹簧表示。重要的是沿链的长度方向要有一个局部坐标系,使弹簧属性能正确的定义。两个RBE2's用于从链轮力矩臂延伸。弹簧附着在这些力矩臂的末端,应为零长度。RBE2's应该是的力矩臂在90度角位置。Thechainistypicallyrepresentedwithaverystiffspring.Itisimportanttohavealocalcoordinatesystemalongthelengthofthechainsothatthespringisproperlydefined.TwoRBE2’sareusedtoextendfromthesprocketmomentarms.Thespringisattachedtotheendofthesemomentarmsandshouldbezerolength.TheRBE2’sshouldbeata90-degreeangletothemomentarm.行星齿轮组OrbitalGearSetsMPC表MPCForm最简单的方法来建模行星齿轮组是在重合节点上建立表示齿轮比的MPC。需要一个惯性术语来表示旋转质量。这一术语将是一个估计,因为行星齿轮组的复杂性，每个齿轮组不能精准获取,因为每个齿轮的真实速度不代表只有输入和输出速度。ThesimplestwaytomodelorbitalgearsetsistousecoincidentgridsandconnectthemwithanMPCequationrepresentingthegearratiooftheset.Aninertiatermisneededtorepresenttherotatingmass.Thistermwillbeanestimatebecauseofthecomplexnatureofanorbitalgearset.Theexactmomentumofeachgearcannotbecomprehendedbecausethetruevelocityofeachgearisnotrepresented—onlytheinputandoutputvelocitiesarerepresented.详细模型DetailedModel一个显着更复杂,但更精确的模型可以通过建模所有独立的齿轮来建立。这是通过为每个旋转组件制作一个节点,并将每个节点用适当的MPC关联来完成的。每个组件的惯性信息应在每个节点上。Asignificantlymorecomplex,butmuchmoreaccuratemodelcanbebuiltbymodelingalloftheindividualgearsinthegearsets.ThisisaccomplishedbymakingonegridforeachoftherotatingcomponentsandtyingeachnodetogetherwithanappropriateMPCtorelatethespeeds.Theinertiainformationforeachcomponentshouldbeoneachgrid.每个齿轮的速比应参考整个减速器的一个输入节点。当变速器换档时,这个输入节点可能会变化。Eachgear’sspeedratioshouldbereferencedtooneinputgridforthewholetransmission.Thisinputgridmaychangeasthetransmissionshiftsgears.行星齿轮需要特别注意。他们的齿轮比应该只反映他们的自转轴,而不是中心载体的转变。因此,它们的质量应增加到载体,而不是他们的转动惯量。例如,如果一个行星系统的太阳/环比为0-.725,而载体/环比为0.441,总行星/环比为2.551,则为行星MPC使用的传动比为2.44。在CONM2卡上的载体的转动惯性应该是载体(行星数)x(一颗行星的质量)x(从太阳中心到行星中心的距离)的实际惯性。对行星CONM2的惯量只应该是绕其自身轴的转动惯量。Planetgearsneedspecialattention.Theirgearratioshouldonlyreflecttheirrotationabouttheirownaxis,andnottheirrevolutionaboutthecenterofthesystemonthecarrier.Consequently,theirmassshouldbeaddedtothecarrier’s,butnottheirrotationalinertia.Forexample,ifaplanetarysethasasun/ringratioof-0.725,andacarrier/ringratioof0.441,withatotalplanet/ringratioof2.551,thegearratiotousefortheplanetMPCis2.44.TherotationalinertiaofthecarrierputontheCONM2cardshouldbetheactualinertiaofthecarrierplus(numberofplanets)x(massofoneplanet)x(distancefromcenterofsuntocenterofplanets).TheinertiaputontheCONM2fortheplanetshouldonlybetherotationalinertiaaboutitsownaxis.在制定mpc的时候,要记得补偿动力总成的转动是非常重要的。ItisveryimportanttoremembertocompensatefortherotationofthepowertrainwhenformulatingtheMPC’s.普通齿轮组OrdinaryGearSets集中质量的转动惯量RotationalInertiaonLumpedMass就像链条链轮一样,齿轮应该有质量和转动惯性放在CONM2卡上。刚性连杆表示齿轮力矩臂。Justlikeachainsprocket,agearshouldhaveitsmassandrotationalinertiaputonaCONM2card.RigidLinkRepresentingGearMomentArm此外,就像一个链链轮,最好的方式来表示齿轮是一个刚性杆代表的间距半径的齿轮。它应该与其他齿轮与一个非常刚的弹簧啮合。另外,弹簧应定义局部坐标系,它应该附加到刚性杆单元的90度角。使用这种方法,一定程度上轴承上正确的力将被了解,然而,除非实际的压力角在两个齿轮之间使用,力是不会绝对正确的。见图3的示意图。Also,justlikeachainsprocket,thebestwaytorepresentthegeariswitharigidbarrepresentingthepitchradiusofthegear.Itshouldbemeshedwithothergearswithaverystiffspring.Again,alocalcoordinatesystemshouldbeusedtodefinethespring,anditshouldattachtotherigidbarelementata90-degreeangle.Usingthismethod,somelevelofthecorrectforcesatthebearingswillbecomprehended,however,unlesstheactualpressureangleisusedbetweenthetwogears,theforceswillnotbeabsolutelycorrect.Seefigure3foraschematic.图3齿轮模型-MPCMPC方程可以用来简单地将两个齿轮的旋转位移联系起来,而不是用力矩臂来逼近齿轮。但是,这种方法值得注意是不会会给出精确的承载力。Ratherthanusingamomentarmapproachtogears,MPCequationscanbeusedtosimplyrelatetherotationaldisplacementsofthetwogears.However,thismethodisnoterecommended,andwillgiveinaccuratebearingforces.齿轮轴GearShafts齿轮、链轮、扭矩转换器和离合器包连接的轴通常是用非常硬的梁单元或刚性单元来模拟的。两者都可以使用，不过要注意刚性单元循环。如果使用RBE2,则应定义所有6个自由度。Theshaftstowhichthegears,sprockets,torqueconverter,andclutchpacksareattachedareoftenmodeledwitheitherverystiffbeams,orrigidelements.Eithercanbeused,however,becarefulofrigiddependencyloops.IfanRBE2isused,all6DOFSshouldbedefined.扭矩转换器TorqueConverterMPC扭矩转换器可以用CONM2卡上的质量和转动惯量来模拟。输出轴的输入可以通过MPC连接。这是使用扭矩转换器的失速比率。通过翻转失速率,确定"速比"。在MPC卡上使用这个比率将会给出扭矩转换器的一些表示。然而,这有一些严重的限制。这个模型在高频下是不准确的。ThetorqueconvertercanbemodeledwiththemassandtherotationalinertiaonaCONM2card.TheinputtooutputshaftscanbeconnectedviaanMPC.Thestallratioofthetorqueconverterisusedforthis.Byinvertingthestallratio,a"speedratio"isdetermined.UsingthisratioontheMPCcardwillgivesomerepresentationofthetorqueconverter.However,thishassomeseriouslimitations.Thismodelisknowntobeinaccurateathigherfrequencies.阻尼器Damper一个阻尼器可以用于扭矩转换器的建模。通过这个模型,通过速度得到输入到输出的关系。这是一个理论上更准确的模型,但非常复杂,在更高的频率范围内仍然存在重大问题。Adampercanbeusedtomodelthetorqueconverter.Withthismodel,therelationshipfrominputtooutputisthroughvelocities.Thisisatheoreticallymoreaccuratemodel,butisextremelycomplex,andstillhassignificantproblemsinthehigherfrequencyranges.差速器Differential差速器是一种用于允许左、右车轮以不同速度移动的装置。这使得车辆容易转弯。差速器旋转输入时差速器两个输出的平均速度。这是一个相当复杂的设备,可能需要一些时间才能适应。在横向安装的动力总成中,差速器在变速器内部。在纵向动力总成上,差速器常在变速器和车后部。请参阅相关文件程序,了解关于差速器的建模。Thedifferentialisadevicethatisusedtoallowtheleftandrightwheelstomoveatdifferentspeeds.Thisallowseasycorneringofthevehicle.Theinputtothedifferentialspinsattheaveragespeedofthetwooutputstothedifferential.Thisisafairlycomplicateddevice,andcantakesometimetogetusedto.Onatransversemountedpowertrain,thedifferentialisinsidethetransmission.Onalongitudinalpowertrain,thedifferentialisoftenoutsidethetransmissionandintherearofthevehicle.Seethedrivelineprocedurefordetailsonmodelingthedifferential.柔性动力总成模型FlexiblePowertrainModels详细动力总成是用实体单元或实体与壳单元相结合的方法建模。由于车辆系统分析的详细动力总成模型是由XX动力总成部门提供的,因此本章没有具体的建模准则。Thepowertrainismodeledindetailusingsolidelementsoracombinationofsolidandshellelements.SincethedetailedpowertrainmodelforvehiclesystemanalysisissuppliedbyXXPowertraingroup,nospecificmodelingguidelinesareincludedinthischapter.当使用柔性动力总成模型时,橡胶动力总成悬置可以用实体单元/壳单元建模，也可以向前面说的用弹簧单元/阻尼单元建模。实体/壳单元模型通常比弹簧/阻尼单元模型更准确。但是,不像弹簧/阻尼模型那样方便地在整车水平上进行安装速率优化。液压动力总成安装应建模为多弹簧-阻尼,如前一节所述。Whenaflexiblepowertrainmodelisu