Q/SZJ191001-2017NVH座椅建模規(guī)范SpecificationofNVHModelingforseats20XX20XX-XX-XX實(shí)施20XX-XX-XX發(fā)布XXXX汽車工程技術(shù)有限公司發(fā)布Q/SZXX-X-2017NVH座椅建模規(guī)范范圍本標(biāo)準(zhǔn)規(guī)定了術(shù)語和定義、NVH座椅建模方法及結(jié)果處理方法。本標(biāo)準(zhǔn)適用于CAE部門的NVH座椅建模。規(guī)范性引用文件無。術(shù)語和定義無。摘要Abstract商用車的座椅是一個(gè)復(fù)雜的結(jié)構(gòu)和非結(jié)構(gòu)的復(fù)雜裝配。座椅是為駕乘者提供舒適和安全的基本部件。市面上不同車型的座椅大小不一,形狀各異。重要的是獲得可靠的座椅模型，用于車輛的NVH性能評估，用于怠速抖動,光滑路面的性能評定抖動和粗糙的路面振動條件。本文件中將討論座椅裝配的建模準(zhǔn)則,供系統(tǒng)NVH分析。由于座椅裝配模型的復(fù)雜性和程序固定,最好的近似方法只能在特定的條件下定義。Aseatinacommercialvehicleisacomplicatedassemblyofstructuralandnon-structuralcomponents.Seatsareessentialcomponentsprovidingcomfortandsafetyfortheoccupants.Therearevarioussizeandshapesofseatsfordifferentvehiclesonthemarket.ItisimportanttoobtainareliableseatmodelforvehicleNVHperformanceassessmentforidleshake,smoothroadshakeandroughroadshakeconditions.ThemodelingguidelinesofseatassemblyaretobediscussedinthisdocumentforsystemNVHanalysis.Duetothecomplicatednatureoftheseatassemblymodelandprogramtiming,abestapproximationmethodcanonlybedefinedwithcertaingivenconditions.、

流程圖ProcessFlowDiagram圖1圖1流程圖Fig1ProcessFlowDiagram座椅CAD模型seat-in-whiteCADmodel建立簡化模型BuildSimpleModel建立詳細(xì)模型BuildSimpleModel模態(tài)計(jì)算SubmittoNastranorOptistruct模型配重CheckModelMass模型輸出ModelCheckout: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):MSC.Nastran或OptiStruct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(shí)間(Time) 秒(Second)內(nèi)容Contents有限元的模型內(nèi)容包括結(jié)構(gòu)特征，有幾何和材料屬性，內(nèi)飾質(zhì)量，以及地板與座椅導(dǎo)軌連接的邊界條件。Thecontentsofthefiniteelementmodelshouldincludeastructuralrepresentation,composedof坐標(biāo)系CoordinateSystems分析采用整車坐標(biāo)系，有些彈簧需要建局部坐標(biāo)系。Analysisusevehicleglobalcoordinatesystem,andlocalcoordinatesystemsareneededforsomespringsinthetrimmedbody.建模技巧ModelingTechniques商用車的座椅是一個(gè)復(fù)雜的結(jié)構(gòu)和非結(jié)構(gòu)的裝配。座椅包括靠背和坐墊，可以按照以下不同的方式：·簡化座椅模型-總質(zhì)量/慣性矩和/或座椅剛度?！ぴ敿?xì)座椅模型-一個(gè)詳細(xì)的板/殼單元模型金屬結(jié)的座椅構(gòu)造，梁用于模擬金屬絲和泡沫/座椅蓋，其他內(nèi)飾件用集中質(zhì)量。當(dāng)詳細(xì)模型參數(shù)不完整不可用時(shí)，建議使用簡化的座椅模型，為特別研究或座椅設(shè)計(jì)驗(yàn)證時(shí)，一個(gè)詳細(xì)的座椅模型是被推薦的?；跍y試座椅的頻率傳遞功能,從座椅軌道/底板到駕駛員座椅底部和座椅靠背位置，可以處理為一些粗糙的道路平順性度量評估或優(yōu)化。座椅背部和底部傳遞的準(zhǔn)確性仍然取決于座椅軌道響應(yīng)的可靠性。座椅對地板的動態(tài)效果影響非常重要,單憑單向傳遞函數(shù)可能無法表示此效果。簡化建模技巧由于時(shí)間或缺乏驗(yàn)證設(shè)計(jì)無法提供詳細(xì)座椅模型，簡化座椅模型，有三個(gè)簡化模型的常用類型：·簡化模型的軟連接：通過RBE3連接，采用集中質(zhì)量（conm2）與地板進(jìn)行連接。將質(zhì)量/慣量分布到與地板連接位置上。座椅質(zhì)量用集中質(zhì)量單元（conm2）模擬，于CG代表其質(zhì)量、慣量模擬?？赏ㄟ^座椅臺架的擺動試驗(yàn)或估算得到。集中質(zhì)量單元通過RBE3與地板進(jìn)行連接固定。圖2簡化座椅軟連接Fig2SimplifiedSoftSeat·座椅質(zhì)量用集中質(zhì)量單元（conm2）模擬，集中質(zhì)量單元通過RBE2用彈簧單元(CELAS2)與地板進(jìn)行連接固定。座椅是用集中質(zhì)量單元conm2表示質(zhì)量和轉(zhuǎn)動慣量，可以通過硬件或擺動試驗(yàn)得到的估計(jì)模型。集中質(zhì)量單元通過剛性單元RBE2與地板進(jìn)行連接，約束自由度123，集中質(zhì)量單元CONM2依附于剛性單元RBE2的主點(diǎn)。座椅與地板之間的連接可以通過彈簧單元CELAS2進(jìn)行連接.假設(shè)在每個(gè)方向上的所有連接位置都有相等的剛度，這些彈簧單元的剛度值被調(diào)整為近似值。圖3列出駕駛員座椅與地板4個(gè)連接處。由于該模型是線性分析，通過平動自由度來調(diào)整彈簧剛度，所以同螺栓、鉤銷之間與地板連接沒有區(qū)別。圖3簡化座椅模型與地板的4個(gè)連接Fig3(SimplifiedTunedSeatwith4FloorConnections注:集中質(zhì)量單元conm2和慣性特性可以單獨(dú)代表座椅總成，或座椅和乘員，取決于分析的類型（模態(tài)分析或道路響應(yīng)/怠速抖動分析）。相關(guān)的模態(tài)驗(yàn)證，正常的模態(tài)測試車輛是沒有乘員的。然而，PSD路譜采集時(shí)必須包括駕駛員。·集中的質(zhì)量/慣量，調(diào)整座椅靠背的剛度(調(diào)整座椅靠背角度)-兩個(gè)集中質(zhì)量單元通過彈簧單元（CELAS2）模擬兩端座椅靠背剛度。整個(gè)座椅質(zhì)量/轉(zhuǎn)動慣量被分為一個(gè)在座椅底部CG(m1)和另一個(gè)在座椅靠背CG（M2），如圖4.3.1-3所示。M1的連接建模與簡化的軟座椅連接相似。座椅靠背和座椅底座用H型鉸鏈進(jìn)行連接。M1上通過6個(gè)自由度全約束的剛性單元RBE2連接到H型鉸鏈上。M2也是通過6個(gè)自由度全約束的剛性單元RBE2連接到H型鉸鏈。圖4簡化座椅靠背模型Fig4SimplifiedTunedSeatBackModel有一對重合的單元連接H型鉸鏈，Y向轉(zhuǎn)動DOF5控制座椅靠背的前后轉(zhuǎn)動，X向轉(zhuǎn)動DOF4來調(diào)節(jié)座椅靠背的橫向運(yùn)動。轉(zhuǎn)動彈簧剛度(K4和K5)可以分別調(diào)整，分別調(diào)節(jié)橫向和前后運(yùn)動模式，以匹配實(shí)驗(yàn)測試或早期車輛開發(fā)計(jì)劃。詳細(xì)的建模技術(shù)座椅軌道與地板有各種不同的連接方式。通常座椅有限元模型由座椅供應(yīng)商建立。座椅模型要適用于噪聲和振動分析的系統(tǒng)模型。詳細(xì)的座椅模型實(shí)例圖5圖5簡化座椅靠背模型Fig5(SimplifiedTunedSeatBackModel座椅總成一般可分為兩部分:座椅骨架(SIW)和座椅附件。座椅骨架（SIW）采用殼，梁單元，和彈簧單元進(jìn)行詳細(xì)建模。座椅用集中質(zhì)量單元或非結(jié)構(gòu)質(zhì)量單元建模。一個(gè)集中質(zhì)量單元通過RBE3分布一個(gè)區(qū)域內(nèi)，有多少RBE3和集中質(zhì)量相連接取決于座椅類型，在圖6中顯示了一個(gè)相對詳細(xì)的座椅內(nèi)飾質(zhì)量的例子。分析人員應(yīng)該驗(yàn)證座椅模型是否設(shè)計(jì)合理，質(zhì)量/慣性，質(zhì)心，以及是否與一些適當(dāng)?shù)臏y試數(shù)據(jù)相吻合。圖6駕駛員座椅的質(zhì)量分布例子Fig6AnExampleofTrimmedMassDistributionforaDriver’sSeatAssemblyAseatinacommercialvehicleisacomplicatedassemblyofstructuralandnon-structuralcomponents.Seats,includingbucketseatsandbenchseats,canbemodeledinthefollowingdifferentways:·Simplifiedseatmodel–lumpedmass/momentofinertiaand/orseatstiffnessareused.·Detailedseatmodel-adetailedplate/shellelementmodelfortheseatmetalstructures,beamelementsformetalwires,andlumpedmassforfoams/seatcoversandothertrimmeditems.Asimplifiedseatmodelisrecommendedwhenavalidateddetailedmodelisnotavailable.Forspecialstudyorseatdesignvalidation,adetailedseatmodelisrecommended.Notethatatestbasedseatfrequencytransferfunctionsfromseattrack/floortodriverseatbottomandseatbacklocationscanbetreatedasapost-processforsomeroughroadridemetricevaluationoroptimization.Theaccuracyoftheresponsesontheseatbackandthebottomstilldependsonthereliabilityoftheseattrackresponses.Theseatdynamiceffectonthefloorisveryimportant,andtheone-waytransferfunctionsalonemaynotbeabletorepresentthiseffect.SimplifiedModelingTechniqueDuetotimingorlackofvalidateddesignintentdetailedseatmodels,simplifiedseatmodelsareusuallyapplied,Therearethreecommontypesofsimplifiedmodels:·Lumpedmass/inertiawithnostiffness(SoftSeat)-ACONM2forthewholeseatwithRBE3todistributethemass/inertiatotheconnectingfloorlocations.TheseatismodeledusingoneCONM2elementlocatedatitsCGtorepresentitsmassandinertiathatcanbeobtainedbyswingtestoftheseathardwareorestimate.RBE3elementsareusedtoconnecttheCONM2elementtothefloorattachmentlocations.·Lumpedmass/inertiawithtunedstiffness(TunedSeat)–ACONM2forthewholeseatwithRBE2spidertoitsfloorlocationsandconnectingtothefloorwithspring(CELAS2)elements.TheseatismodeledusingoneCONM2elementlocatedatitsCGtorepresentitsmassandmomentsofinertia.Coincidentgridsarecreatedattheseat-floorconnectionlocations.RBE2elementsareusedtoconnecttheCONM2elementtothesecoincidentgridsintheDOF123.TheCONM2elementshouldbeplacedattheindependentgridoftheRBE2elements.OnlyDOF123areneededfortheRBE2spiderconnections.TheCONM2shouldbelocatedattheindependentgridofthespider.TheconnectionsbetweenthecoincidentgridsandtheflooraremadebytheCELAS2springelements.Assumingequalstiffnessratesatalltheseattachmentlocationsineachdirectionrespectively,thestiffnessvaluesofthesespringelementsaretunedtoapproximatethelateral,verticalandfore/aftmodesoftheseatbasedonavailabletestdataforroughroadvibrationsimulation.Figure4.3.1-2showsanexampleofdriverseatwith4connectionlocationsatthebodyfloor.SincethemodelisusedinalinearanalysisandonlyDOF123(translationalDOF)areconsideredinthetunedspringstiffness,nodistinctionismadebetweenabolt-onandahook-pinconnectionatthefloor.NOTE:ThemassandinertiapropertiesoftheCONM2canrepresenttheseatassemblyalone,ortheseatassemblyandoccupant,dependingonthetypeofanalysisbeingdone(i.e.,normalmodesanalysisorroadresponse/idleshakeanalysis).Thereasonisthatwhencorrelatingtomodaltests,anormalmodeslaboratorytestisdonewithnooccupantinthevehicle.However,aPSDroadresponsemeasurementmustincludethedriver.·Lumpedmass/inertiawithtunedseatbackstiffness(TunedSeatBack)–TwoCONM2elementsandtwoseatbackstiffnessrateswithspring(CELAS2)elements.Thewholeseatmass/momentofinertiaisdividedintooneattheseatbottomCG(m1)andintoanotheroneattheseatbackCG(m2)asshowninFigure4.3.1-3.Theconnectionmodelingofm1issimilartothatofthesimplifiedsoftseat.TheJointHisdefinedasthehingelocationbetweentheseatbackandtheseatbottom.Thegridatm1isconnectedtothejointHusingRBE2withall6-DOFs.ThejointHisconnectedtogridatm2byaRBE2withall6-DOFs.ThereisapairofcoincidentgridsforthejointHthatcanonlyrotateintheDOF5forseatbackfore/aftandDOF4forseatbacklateralmotions.Therotationalspringstiffnessrates(K4andK5)canbetunedrespectivelytomatchthelateralandfore/aftvibrationmodesoftheseatbackfromalabtestorfromaspecificationinaearliervehicleprogram.DetailedModelingTechniqueTherearevarioustypesofseatstructuresandseattrack-to-floorconnections.Thedetailedseatmodelsinfiniteelementsarenormallybuiltbyseatsuppliers.BothSMTandSystemmodelsfornoiseandvibrationanalysesapplythereceivedseatmodels.SomeoftheexamplesofthedetailedseatmodelsareshowninFigures5.Componentsoftheseatassemblycanbegenerallydividedintotwogroups:seat-in-white(SIW)andseattrim.ASIWismodeledindetailusingshell,beam,andspringelementsasstated.SeattrimismodeledusingeitherCONM2ornon-structuralmassasstatedinthisdocument.ThelumpedmassofaCONM2isdistributedoveranareabyRBE3spider.HowmanyRBE3spidersandwheretoconnectthemdependsontheseattypeandtherelativesignificanceofthelumpedmass.ArelativedetailedexampleofmodelingtheseattrimmedmassisshowninFigure6.Thesystemanalystshouldverifythattheseatmodelrepresentstherightdesignlevel,themass/momentofinertia,centerofmass,andifithasbeencorrelatedtosomeappropriatetestdata.假設(shè)和限制Assumptions/Limitations在給定的條件下，座椅模型的動力學(xué)性能是線性的。Thedynamicsperformanceoftheseatmodelsislinearforagivenoperatingconditio