Q/SZJ191001-2017內(nèi)飾車身噪聲和振動建模規(guī)范NoiseandVibrationTrimmedBodyModelling20XX20XX-XX-XX實施20XX-XX-XX發(fā)布XXXX汽車工程技術(shù)有限公司發(fā)布Q/SZXX-X-2017內(nèi)飾車身噪聲和振動建模規(guī)范范圍本標準規(guī)定了術(shù)語和定義、內(nèi)飾車身噪聲和振動模型的建模方法。本標準適用于CAE部門的內(nèi)飾車身噪聲和振動建模。規(guī)范性引用文件無。術(shù)語和定義無。摘要AbstractNVH系統(tǒng)建模按車輛的承載能力分為兩類：結(jié)構(gòu)部件：這些都是與白車身連接到一起的部件（BIW）。例如包括中通道，IP橫梁和門內(nèi)板。非結(jié)構(gòu)部件（附件）：這些部件都是提供很少或沒有承載能力的結(jié)構(gòu)。例如包括電線，外飾。由于我們建模能力的不斷擴大，內(nèi)飾車身建模的精細程度是一個發(fā)展趨勢，詳細說明了小承載能力的部件，這些先進的建模技術(shù)將對個別部件進行詳細討論。非結(jié)構(gòu)部件大部分對整車的剛度沒有影響。只有它們的質(zhì)量、慣量矩和/或阻尼特性在車輛系統(tǒng)建模中被模擬。一般來說，非結(jié)構(gòu)性組件建模有兩種方法:?簡化建模:這個組可以進一步細分為組件模型:集中質(zhì)量:包括尺寸較小的部件，通過剛性單元連接到車身（BIW）一個或多個部分。例如包括電池、剎車助力器和加速踏板通過分布質(zhì)量進行模擬:這些部件通常較大，并且通過一個特定的區(qū)域進行傳遞。例如白車身面板上的油漆。?詳細建模:這些部件通常對局部剛度和質(zhì)量貢獻量較大。例如地板上的地毯和隔音板的建模，能額外增加剛度和阻尼。建立完整的模型取決于以下：?項目可交付成果/時間?資源（分析人員處理模擬細節(jié)的情況）?數(shù)據(jù)/信息的可用性(設(shè)計可能不成熟，無法提供詳細的數(shù)據(jù))?分析目標(結(jié)果保真度)對內(nèi)飾部件模擬方式的選擇決定了相應(yīng)分析結(jié)果的有效性。模型建立的越詳細，該模型的有效性就越高，在結(jié)構(gòu)噪聲頻率范圍內(nèi)，該模型的有效性越高。車輛建模時包括所有的重要質(zhì)量，使模型質(zhì)量與實際車輛質(zhì)量相匹配是非常重要的。車輛模型的質(zhì)量不僅要準確地反映實際的車輛質(zhì)量，而且要根據(jù)實際情況在整車中正確地分布，同時也要考慮到大型部件的慣量值。NVHsystemmodelingmakesafunctionaldivisionofthecomponentsofavehicleintotwocategoriesbasedontheirload-carryingcapability:·structuralcomponents:Theseareloadcarryingmemberscommonlyassociatedwiththebody-in-white(BIW).Examplesincludelongitudinalrails,IPbeams,anddoorinnerpanels.·non-structuralcomponents(or“trim”components):Thesearecomponentsthatprovidelittleornoloadcarryingcapabilitytothefullvehiclestructure.Examplesincludetheelectricalwiring,andexteriorstylingtrim.Asourcapabilityinmodelingexpands,thereisagrowingtrendtomodeltrimcomponentsindetailtoaccountfortheminorloadcarryingcapability.Theseadvancedmodelingtechniqueswillbediscussedindetailonanindividualcomponentbasis.Thisprocedureisconcernedprimarilywiththemodelingofthenon-structuralcomponents.Themodelingofthemostcommonnon-structuralcomponentsacrossallvehicleplatformsisdescribedhere.Mosttrimcomponentsprovidenosignificantstiffnesscontributiontotheoverallvehicle.Onlytheirmass,momentsofinertia,and/ordampingcharacteristicsaresimulatedinvehiclesystemmodeling.Ingeneral,non-structuralcomponentscanbeidealized/modeledintotwomaingroups:? Simplerepresentation:Thisgroupcanbefurthersub-dividedintocomponentsmodeledas:Concentratedmass:ThisincludespartsthatareusuallysmallinsizeandattachedtotheBIWatoneorseveralpoints.Examplesincludethebattery,brakebooster,andacceleratorpedalDistributedmass:Thesecomponentsareusuallylargeinsizeandspreadthroughaspecificarea.ExamplesincludethepaintontheBIWpanels.? Detailedrepresentation:Thesecomponentsareusuallydeemedsignificantintheircontributiontolocalstiffnessandmass.Anexampleismodelingthecarpetanddeadeneronthefloorpanelstoaccountforadditionalstiffnessanddamping.Selectingtheappropriaterepresentationforatrimcomponentwilldependon:? Programdeliverables/timing? Resources(HPCandanalysttoprocessthedetailinthemodel)? Availabilityofdata/information(designmaybetooimmaturefordetaileddata)? Analysisobjectives(fidelityofresultsrequired)Theparticularselectionofarepresentationfortrimcomponentswillqualifythevalidityofthecorrespondinganalysisresults.Thehigherthedetailcontentofthemodel,themorepotentialtopushthevalidityofthemodeltohigherfrequenciesinthestructurebornenoisefrequencyrange.Itisimportanttoincludeallsignificantmassesinthevehiclemodelsothatthemodelmasscorrectlymatchestherealvehiclemass.Themassofthevehiclemodelshouldaccuratelyreflecttherealvehiclemassnotonlyinoverallweight,butalsointheproperdistributionthroughoutthevehicleandalsowiththeappropriateinertiavaluesforlargecomponents.流程圖ProcessFlowDiagram座椅座椅CAD模型seat-in-whiteCADmodel建立簡化模型BuildSimpleModel建立詳細模型BuildSimpleModel模態(tài)計算SubmittoNastranorOptistruct模型配重CheckModelMass模型輸出ModelCheckout: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):MSC.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ContentsTrimmedbody包含所有重要的質(zhì)量。Trimmedbody應(yīng)包含：白車身、發(fā)動機罩、行李箱、擋板、地毯、頂蓋內(nèi)飾板、散熱器總成、制動助力器、電池、備胎、座椅、阻尼器、安全帶、轉(zhuǎn)向管柱、洗滌液瓶、雨刷、ABS控制器的、計算機模塊、非結(jié)構(gòu)車身、車門等。任何重要的質(zhì)量都必須包括在內(nèi)。每個內(nèi)飾部分的質(zhì)量，以及搭建的總質(zhì)量必須與實際內(nèi)飾車身質(zhì)量相匹配。Thetrimmedbodyshouldcontainallofthesignificanttrimmedmasses.Thetrimmedbodyshouldcontain:Bip,Hood,decklid,tailgate,carpet,headliner,radiatorassembly,brakebooster,battery,sparetire,seats,bakeondampers,seatbelts,steeringcolumn,washerbottle,windshieldwipers,ABScontroller,computermodules,nonstructuralbodypanels,doorsandetc.Anysignificantconcentratedordistributedmassesmustbeincluded.Themassofeachtrimpart,aswellasthetotalmassofthetrimbodymustmatchtheactualmassofthetrimmedbody.坐標系CoordinateSystems分析采用整車坐標系,有些彈簧需要建局部坐標系。Analysisusesvehicleglobalcoordinatesystem,Localcoordinatesystemsareneededforsomespringsinthetrimmedbody.建模技巧ModelingTechniques簡化的建模技術(shù)?3D單元內(nèi)飾建模建模包括大質(zhì)量和慣量的部件（＞3kg）。質(zhì)量和慣量等效為集中質(zhì)量和轉(zhuǎn)動慣量（conm2）。對于大質(zhì)量部件（＞3kg），具有顯著的慣量特性，建議把這些慣量值附在集中質(zhì)量單元（conm2）上，這些屬性會顯著影響系統(tǒng)模型的動態(tài)特性。內(nèi)飾附件用剛性單元（RBE2、RBE3）與白車身進行連接。剛性單元應(yīng)該按照實際的位置范圍進行連接，集中質(zhì)量附在部件的質(zhì)心位置，RBE2是剛性單元能增加剛度，RBE3單元本身不提供剛度。對于非常硬的部件（雨刮電機和支架），就要用RBE2單元來模擬相對剛性的附件。然而，大部分的組件建模都采用詳細模型，因為它能夠精準的反映部件與部件之間的連接關(guān)系。此外，當用剛性單元建模時，必須考慮剛性單元自由度。一般建模方法用剛性單元和集中質(zhì)量。圖2簡化建模方法Fig2GeneralmodelingtechniqueRBE2剛性單元主點和從點都有6個自由度。一般建模方法用集中質(zhì)量。圖3簡化建模方法RBE3Fig3GeneralmodelingtechniqueRBE3主點是6個自由度，從點有1-3自由度。對具有顯著的慣性特性的轉(zhuǎn)動剛體模態(tài)的部件，使用剛度單元RBE2在質(zhì)心位置加集中質(zhì)量點。?2D單元內(nèi)飾建模（通過多點連接到車身）參考之上描述的3D建模方法。2D單元非結(jié)構(gòu)質(zhì)量（附與在車身上的區(qū)域）質(zhì)量和附件采用非結(jié)構(gòu)質(zhì)量單元模擬（NSM,NSM1），在屬性Pshell卡片里設(shè)置非結(jié)構(gòu)質(zhì)量單元NSM。2D單元部件的剛度（附加在白車身一個區(qū)域內(nèi)），質(zhì)量、阻尼和內(nèi)飾附件模擬都要仿照實際車輛狀況來定義板件屬性。?1D單元質(zhì)量為集中質(zhì)量（conm2），慣量通常被忽略。附件直接與白車身結(jié)構(gòu)安裝孔進行連接。為了與實際車輛重量匹配，可以通過集中質(zhì)量進行配重。SimplifiedModelingTechnique?3D“Block”TrimComponentsTheseincludetrimcomponentsofsignificantmass(>3kg)andinertia.Massandinertiaismodeledasconcentratedmassandinertia(CONM2).Forlargecomponents(>3kg)thathavesignificantinertiaproperties,itisrecommendedthattheseinertiavaluesbeincludedintheCONM2element,asthesepropertiesmaysignificantlyaffectthebehaviorofthesystemmodel.AttachmenttotheBIWismodeledwithrigidelements(RBE2orRBE3).Therigidelementsshouldattachtothevehiclestructureinthesamelocationsasthecomponentattachmentswhosemassisbeingmodeled.BewarethatRBE2elementsaddinfinitestiffnessandRBE3elementsaddzerostiffness.Forverystiffcomponents(suchasthewindshieldwipermotorandbrackets),anRBE2elementspidershouldbeusedtomodelthisrelativelyrigidattachment.However,mostcomponentsthataremodeledarelessrigidlyattached.Therefore,anRBE3spidershouldbeusedinthesecasesbecauseitprovidesamoreaccuraterepresentationofthecomponentanditsattachmenttothevehiclestructure.Also,whenmodelingwithrigidelements,considerationmustbegiventowhatdegreesoffreedom(DOF’s)areused.GeneralmodelingtechniqueusedforRBE2/CONM2representation:RBE2：DependentGrids(DOF1-6)RBE2：IndpendentGrids(DOF1-6)GeneralmodelingtechniqueusedforRBE3/CONM2representation:RBE3：DependentGrids(DOF1-6)RBE3：IndpendentGrids(DOF1-3)VisualizationofrotationalrigidbodymodesoftrimcomponentswithsignificantinertiamayrequireavisualizationRBE2attachedtotheCG/CONM2point.?2D“Sheet”TrimComponents(AttachedtotheBIWatafewpoints)See3D“Block”TrimComponents(above)?2D“Sheet”TrimComponents(AttachedtotheBIWoveranarea)Massandattachmentismodeledasnon-structuralmass(NSM,NSM1orfield9onPSHELLcard)onthestructuralelementsthatthecomponentisattachedto.Formassbookkeepingpurposes,therecommendationistouseNSMLorNSML1asmultipletrimcomponentssmearedontoonePSHELLcardremovesaccountabilityofmass.?2D“Sheet”TrimComponentswithstiffness(AttachedtotheBIWoveranarea)Stiffness,Mass,DampingandattachmentismodeledusingduplicateelementsontheexistingstructuralBIWmodelwithreferencetotheirownindividualpropertycard(PSHELL).?1D“Line”TrimComponentsMassismodeledasconcentratedmass(CONM2)andinertiaisusuallyneglected.AttachmentisdirecttoexistingpointsontheBIWstructure.VisualizationofthetrimcomponentcanbeexecutedwithPLOTELsconnectingtheconcentratedmasses(CONM2s)forthepurposesofmassaccountability.詳細的建模方法參照下面列出的內(nèi)飾部件電池建模：簡化模型，模型講解：這部分采用剛性單元把集中質(zhì)量及慣量附加到質(zhì)心位置上，與電池托盤進行連接來模擬電池結(jié)構(gòu)。集中質(zhì)量單元與電池托盤的連接結(jié)構(gòu)如下：單元類型：RBE2主點：集中質(zhì)量（conm2）加載在主點上，自由度1-6從點：電池與托盤的接觸面積大概選15個網(wǎng)格范圍，此接觸面積不是真正的接觸面積，而是電池與電池支架連接產(chǎn)生的預(yù)應(yīng)力接觸面積，通常取電池托盤面積的40%，不要過度限制電池托盤的面積。從點自由度：1-6詳細建模：無圖4電池簡化模型RBE3Fig4BatterySimpleModelBatteryModelingSimpleModel,ModelingNotes:ThiscomponentismodeledusingoneCONM2elementlocatedatitsCGandanRBEelementtoattachittothebatterytraystructure.InertiaisREQUIRED.TheattachmentfromtheCONM2tothebatterytraystructureshouldbeasfollows:ElementType: RBE2IndependentGrid: CONM2GRIDIndependentDOF: 1-6DependentGrids: Minimumnumberis15MappedtocontactareaofBatteryontray.ThiscontactareaisNOTthe“touching”contactarea,butthesignificantpre-stressedcontactareaduetobatterytiedown.Traditionallythisareaisabout40%oftotalbatterytrayarea.Donotoverconstrainthebatterytray.DependentDOF: 1-6詳細建模：無DetailedModel：NotAvailable揚聲器建模：簡化模型，模型講解：這部分建模把集中質(zhì)量點和慣量附加在質(zhì)心上，通常剛性單元連接范圍在門內(nèi)板上。設(shè)計部門提供慣量：單元類型：RBE3從點：集中質(zhì)量（conm2）加載在從點上主點：車門內(nèi)板螺栓或者螺釘孔主點自由度：1-3SpeakersModelingSimpleModel,ModelingNotes:ThiscomponentismodeledusingoneCONM2elementlocatedatitsCGandanRBEelementtoattachittothedoorinnerstructure.InertiaisRECOMMENDED.TheattachmentfromtheCONM2tothebatterytraystructureshouldbeasfollows:ElementType: RBE3DependentGrid: CONM2GRIDDependentDOF: 1-6IndependentGrids: Mappedtobolt/screwlocationsondoor.IndependentDOF: 1-3圖5揚聲器簡化模型Fig5SpeakersSimpleModel揚聲器詳細建模，模型講解：該部件可分為部件結(jié)構(gòu)和部件質(zhì)量。揚聲器的支架模型采用殼單元建模，與車門內(nèi)板通過剛性單元或者梁單元來模擬螺栓連接。揚聲器的慣量加在集中質(zhì)量點或RBE3從點上，方法同簡化模型。DetailedModel,ModelingNotes:Thiscomponentcanbesub-dividedintocomponentstructureandcomponentmass.Speaker“housing”ismodeledwithadetailedCQUADRmeshandconnectedtothedoorinnerswithRBE2orCBEAMelementstorepresentthebolts/screws.SpeakerinternalsaremodeledwithaCONM2/RBE3asinthe“simplemodel”圖6揚聲器詳細模型Fig6SpeakersDetailedModel散熱器總成建模：簡化建模，模型講解：用蜘蛛狀多點剛性單元（rbe2）與安裝點進行連接，集中質(zhì)量點加載在剛性單元（rbe2）的主點上，剛性單元（rbe2）的從點通過零長度的彈簧單元與車身側(cè)安裝點進行連接，剛性單元（rbe2）有6個自由度。由于散熱器可以用硬座或使用橡膠墊或襯套與車身進行連接，彈簧用于模擬散熱器的安裝剛度，通常情況下，這些橡膠墊的剛度可以通過測試或者由供應(yīng)商提供。散熱器模擬要有充足的冷卻液，當冷卻密度不可用時，可使用常規(guī)值1.04e-9噸/立方毫米。當彈簧剛度無法提供，用RBE3代替RBE2和彈簧單元，這種方法往往降低了散熱器本身的剛度，應(yīng)謹慎使用這種方法。散熱器安全剛度（彈簧剛度值）KX=50N/mmKY=50N/mmkz=70N/mmRadiatorAssemblyModellingSimpleModel,ModelingNotes:Onespider-shapedRBE2rigidelementshouldbeusedtoconnecttheCONM2elementtothemountinglocationsoftheFESM.TheCONM2elementshouldbeplacedattheindependentgridoftheRBE2andthedependentgridsoftheRBE2elementshouldbeconnectedtotheFESMmountingpointsthroughzero-lengthCBUSHspringelements.AllsixDOFsoftheRBE2elementshouldbeused.Sincetheradiatorcanbeeitherattachedtothebodybyahardmountorbyusingrubberpadsorbushings,theCBUSHelementsusedtomodeltheradiatormountstiffnesswillvaryintheirspringratevalues.Typicallythestiffnessoftheserubberpadscaneitherbemeasuredorobtainedfromthemanufacturer.Theradiatorissimulatedbyassumingthatthereisafullcapacityofcoolant.Whenthecoolantdensityisnotavailable,anominalvalueof1.04e-9tonnes/mm3maybeused.Thoughlessdesirable,whentherubbermountstiffnessisnotavailableRBE3elementswithoutCBUSHspringelementsmaybeusedinsteadofRBE2/CELASelementsasstatedabove.Thismethodtendstounderestimatethestiffnesscontributionofradiatortothebodyandshouldbeusedwithcaution.Nominalratesfortheradiatormountsare:Kx=50N/mmKy=50N/mmKz=70N/mm圖7推薦的簡化建模方法Fig7recommendedmodelingpractice圖8剛度值無法提供時使用的建模方法Fig8ModeltobeUsedifMountTatesareUnavailable散熱器詳細建模，模型講解：一個完全詳細的散熱器模型通常由供應(yīng)商提供。工程師必須對供應(yīng)商交付的模型進行質(zhì)量和模態(tài)相關(guān)檢查。散熱器的側(cè)面安裝點應(yīng)采用剛性單元rbe2連接，并與彈簧單元連接，彈簧單元代表了散熱器的安裝剛度和阻尼。散熱器詳細建模，模型講解：一個完全詳細的散熱器模型通常由供應(yīng)商提供。工程師必須對供應(yīng)商交付的模型進行質(zhì)量和模態(tài)相關(guān)檢查。散熱器的側(cè)面安裝點應(yīng)采用剛性單元rbe2連接，并與彈簧單元連接，彈簧單元代表了散熱器的安裝剛度和阻尼。RadiatorAssemblyDetailedModel,ModelingNotes:AfullydetailedradiatormodelismostoftenSUPPLIERderived.Theanalystmustperformamassandmodalcorrelationcheckonasupplierdeliveredmodel.MountpointsonradiatorsideshouldbemodeledwithRBE2,andconnectedtotheFESMwithzerolengthCBUSHelementsrepresentingmountstiffness&damping.圖9散熱器詳細模型Fig9RadiatorAssemblyDetailedModel備用輪胎建模簡化模型，模型講解：一個備用輪胎，應(yīng)該用一個剛性單元把集中質(zhì)量和慣量附加在質(zhì)心位置來模擬，通過多點蜘蛛型剛性單元rbe2進行連接，主點為輪胎中心點，從點為輪胎底部與地板接觸的周邊，集中質(zhì)量點和慣量都加在剛性單元主點上。應(yīng)至少使用16個接觸點，并沿一周接觸面均勻分布。剛性單元與地板之間用3個平動自由度彈簧單元進行連接，所有輪胎接觸點都可以使用相同的彈簧剛度。應(yīng)該通過模型的模態(tài)和頻率響應(yīng)與硬件測試關(guān)聯(lián)起來確定的一個值。備胎接觸模擬彈簧剛度值為0.8N/mm/mm。如果備用輪胎的支撐結(jié)構(gòu)導致備用輪胎的共振頻率（局部模態(tài)），那么支承結(jié)構(gòu)應(yīng)該被建模為結(jié)構(gòu)構(gòu)件。這樣的一個例子，輪胎在汽車的尾部，輪胎的托架通常是管狀結(jié)構(gòu)，附在汽車后地板和后擋板之間，管狀結(jié)構(gòu)應(yīng)用梁單元來模擬，表示輪胎本身的結(jié)構(gòu)剛度。當彈簧剛度無法提供，又沒有相關(guān)的測試數(shù)據(jù)來參考，可用RBE3代替剛性單元RBE2和彈簧單元，這種方法往往降低了輪胎本身的剛度，應(yīng)謹慎使用這種方法。SpareTireModellingSimpleModel,ModelingNotes:AsparetireshouldbemodeledusingoneCONM2elementlocatedatitsCGtorepresentitsmassandinertia.Onespider-shapedRBE2rigidelementshouldbeusedtoconnecttheCONM2elementtothefloortiretubatthecenterboltlocationandseveraltire-to-floorcontactlocations.InertiaisREQUIRED.Aminimumof16contactpointsshouldbeusedandevenlydistributedalongthecontactpatch.CBUSHelementswiththreetranslationalstiffnessesshouldbeusedbetweentheRBE2andthefloor.AlltirecontactpatchpointCBUSHelementsmayusethesamestiffnessrates.TheCBUSHstiffnessesshouldbedeterminedbycorrelatingnormalmodesandFRFsofthemodelwiththoseofhardwaretests.NominalvaluesforCBUSH/Contactforsparewheel=0.8N/mm/mmIfthesupportingstructureforthesparetiregeneratesresonantfrequenciesofthesparetire(localmodes),thenthesupportingstructureshouldbemodeledasastructuralmember.Anexampleofthiswouldbethetirecarrierthatsupportsthetireattherearofthevehicle.Thetirecarrieristypicallyatubularstructurethatattachestotherearpillarandtheendgate.ThetubularstructureshouldbemodeledwithCBEAMelementstorepresentthestructuralstiffnessofthecarrier.Thoughlessdesirable,whenthereisnohardwaretestavailableforcorrelationandnohistoricaldataavailableforreference,RBE3elementswithoutCBUSHelementsmaybeusedinsteadofRBE2/CBUSHmethodstatedabove.Thismethodunderestimatesthestiffnesscontributionofsparetiretothebodyandshouldbeusedwithcaution.圖10備用輪胎簡化模型Fig10SpareTireSimpleModel詳細模型，模型講解：應(yīng)該由供應(yīng)商提供詳細的輪胎模型。詳細的模型應(yīng)符合以下參數(shù)：輪胎：采用四邊形和三角形建模輪轂：采用四面體或者六面體建模輪胎的性能參數(shù)應(yīng)通過測試提供，在沒有硬件測試的條件下，輪胎的常規(guī)性能參數(shù)如下：彈性模型：24兆帕泊松比：0.11密度=1.08e-09噸/立方毫米一圈單獨RBE2單元采用點對點與備胎托架的接觸面進行連接。另一個RBE2從外緣內(nèi)表面與中心螺栓孔進行連接。最后,檢查模型質(zhì)量是否與實際質(zhì)量一致。DetailedModel,ModelingNotes:Ifpossibleoravailable,acquirethecompletetire/wheelmodelfromSUPPLIER.Thedetailmeshshouldconformtothefollowingguidelines:Tire:CQUADRandorCTRIARRim:CTETRA10andorCHEX20Thepropertiesofthetirearetunedtohardwaretests.Intheabsenceofhardwaretests,nominalpropertiesofthetireare:E=24MPa=0.11=1.08E-09Tonnes/mm3or(Mg/mm3)AringofindividualRBE2sordirectnode-to-nodecontactwiththesparewheeltubrepresentsthecontact-attachmentconditiontothesparewheeltub.AnRBE2fromtheriminnersurfacetocenterboltattachmenttosparewheeltubrepresentsthesecuringbolt.Finally,thesparewheel/tiremodelshouldbecheckedtohaverepresentativemasswithrespecttohardware.圖11備用輪胎詳細模型Fig11SpareTireDetailedModel座椅建模簡化模型，模型講解：座椅模型把集中質(zhì)量點和慣量附加在質(zhì)心位置來模擬。集中質(zhì)量單元通過RBE3與地板安裝孔進行連接，集中質(zhì)量點附在RBE3的從點上，RBE3的主點有6個自由度。警告：該模型不考慮座椅的運動關(guān)系，不能代表座椅的本體模態(tài)。它能提高車輛結(jié)構(gòu)的連接剛度。SeatModellingSimpleModel,ModelingNotes:TheseatismodeledusingoneCONM2elementlocatedatitsCGtorepresentitsmassandinertia.RBE3elementsareusedtoconnecttheCONM2elementtothefloorattachmentlocations.TheCONM2elementshouldbeplacedatthedependentgridoftheRBE3elements.InertiaisREQUIRED.AllsixDOF’softheRBE3elementshouldbeused.WARNING:Thismodeldoesnotconsidertheseatflexibilityandcannotrepresentseatlocalmodes.Itdoesnotincludethestiffeningeffectontherestofvehiclestructure.圖12座椅簡化模型Fig12SeatSimpleModel詳細模型，模型講解：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。詳細的座椅模型實例圖13：圖13座椅詳細模Fig13SeatDetailedModel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，和彈簧單元進行詳細建模。座椅用集中質(zhì)量單元或非結(jié)構(gòu)質(zhì)量單元建模。一個集中質(zhì)量單元通過RBE3分布一個區(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12中顯示了一個相對詳細的座椅內(nèi)飾質(zhì)量的例子。分析人員應(yīng)該驗證座椅模型是否設(shè)計合理，質(zhì)量和慣量，質(zhì)心，以及是否與一些適當?shù)臏y試數(shù)據(jù)相吻合。DetailedModel,ModelingNotes:Therearevarioustypesofseatstructuresandseattrack-to-floorconnections.Thedetailedseatmodelsinfiniteelementsarenormallybuiltbyseatsuppliers.BothSMTandSystemmodelsfornoiseandvibrationanalysesapplythereceivedseatmodels.SomeoftheexamplesofthedetailedseatmodelsareshowninFigures12.Componentsoftheseatassemblycanbegenerallydividedintotwogroups:seat-in-white(SIW)andseattrim.ASIWismodeledindetailusingshell,beam,andspringelementsasstated.SeattrimismodeledusingeitherCONM2ornon-structuralmassasstatedinthisdocument.ThelumpedmassofaCONM2isdistributedoveranareabyRBE3spider.HowmanyRBE3spidersandwheretoconnectthemdependsontheseattypeandtherelativesignificanceofthelumpedmass.ArelativedetailedexampleofmodelingtheseattrimmedmassisshowninFigure12.Thesystemanalystshouldverifythattheseatmodelrepresentstherightdesignlevel,themass/momentofinertia,centerofmass,andifithasbeencorrelatedtosomeappropriatetestdata.車門建模簡化模型，模型講解：在車門質(zhì)心位置附加一個集中質(zhì)量單元（CONM2）和慣量。剛性單元(RBE2)用于連接鉸鏈和鎖扣位置。集中質(zhì)量單元附在剛性單元的主點上，剛性單元有6個自由度。剛性單元與側(cè)圍連接采用零位移的彈簧單元模擬連接剛度。彈簧剛度由試驗測試得出。工程師可以使用以下典型的鎖緊剛度值：KX=6.7x102牛/毫米，KY=9.0×104牛/毫米，kz=6.7x102牛/毫米。工程師可以使用下面的典型的上鉸鏈剛度值：KX=1.0×104牛/毫米，KY=5.0×104牛/毫米，kz=5.0×104牛/毫米。工程師可以使用以下典型的下鉸鏈剛度值：KX=5.0×104牛/毫米，KY=5.0×104牛/毫米，kz=5.0×104牛/毫米。剛性的車門模型易于創(chuàng)建，只需要少量的計算機資源即可運行。警告：該模型不考慮車門的運動關(guān)系，不能代表車門的本體模態(tài)。它能增強車輛結(jié)構(gòu)的連接剛度。DoorModellingSimpleModel,ModelingNotes:ThedoorassemblyismodeledusingoneCONM2elementlocatedatitsCGtorepresentitsmassandinertia.RBE2elementsareusedtoconnecttheCONM2elementtothedoorhingeandlatchlocations.TheCONM2elementshouldbeplacedattheindependentgridoftheRBE2elements.AllsixDOFsoftheRBE2elementshouldbeused.TheRBE2elementsareattachedtothedoorframeusingCBUSHforthehingeandzero-lengthCBUSHelementstorepresenttheattachmentstiffnessthatthedoormayaddtothebodystructure.InertiaisREQUIRED.ThespringratesoftheCBUSHelementsaredeterminedbycorrelatingwithtestdata.Theanalystmayusethefollowingtypicallatchstiffnessvaluesasastartingpoint:Kx=6.7x102N/mm,Ky=9.0x104N/mm,Kz=6.7x102N/mm.Theanalystmayusethefollowingtypicaltophingestiffnessvalues:Kx=1.0x104N/mm,Ky=5.0x104N/mm,Kz=5.0x104N/mm.Theanalystmayusethefollowingtypicalbottomhingestiffnessvalues:Kx=5.0x104N/mm,Ky=5.0x104N/mm,Kz=5.0x104N/mm.Therigiddoormodeliseasytocreateandneedslittlecomputerresourcetorun.WARNING:Thisrepresentationdoesnotconsiderthedoorflexibilityanddoesnotrepresentdoorlocalmodes.Itmayhaveanover-stiffeningeffectonthebody.圖14車門簡化模型FigDoorSimpleModel詳細模型，模型講解：車門總成可分為兩組：白門和門內(nèi)飾。白門(DIW)使用殼單元（shell）進行詳細的建模，內(nèi)飾部門采用集中質(zhì)量（conm2）和非結(jié)構(gòu)質(zhì)量建模。門鎖使用彈簧單元（CBUSH）來模擬，可以對彈簧剛度進行調(diào)整，使分析模態(tài)結(jié)果與試驗結(jié)果保持一致，前提是測試數(shù)據(jù)準確。彈簧剛度的常規(guī)值可參考上面的“簡化模型”部分。側(cè)圍與車門之前的密封條可以采用彈簧單元（cbush）建模。正常的密封條總的剛度值是3000牛/毫米，即每根彈簧的剛度是由車門彈簧總剛度除以總數(shù)量。密封條剛度直接影響車輛的剛度，并需要提供相關(guān)的測試數(shù)據(jù)。密封條需要建立矢量。應(yīng)采用以下局部坐標系：局部X=指向密封線方向局部y=同全局Y向局部Z=垂直與局部坐標系X和Y向剛性模型和柔性模型這兩種建模方式，柔性建模是最準確的一種。這對聲學分析尤為重要。然而，柔性建模往往會產(chǎn)生大量的自由度，需要較長的時間來建模，并需要更多的計算機資源。DetailedModel,ModelingNotes:Allcomponentsofthedoorassemblyaredividedintotwogroups:Door-in-white(DIW)andDoortrim.EachDIWpartismodeledindetailusingshellelementsasindocument.EachtrimpartismodeledusingeitherCONM2ornon-structuralmassasstatedinthisdocument.ThedoorlatchismodeledusingCBUSHelements.ThespringratesoftheCBUSHelementsshouldbetunedproperlytoaddtherightstiffnesstotherestofvehiclestructuresothattheresultsofadoorandbodystructuremodalanalysismatchthemodaltestresultsunderthesameconditions,ifsuchtestinformationisavailable.Fornominalvaluessee“simplemodel”sectionabove.Theweatherstrips/sealsbetweenbodystructureanddoormaybemodeledusingCBUSHelements.Atypicalvalueoftotalnormalstiffnessis3,000N/mm;i.e.thestiffnessforeachspringelementisthetotalstiffnessdividedbythetotalnumberofspringelementsusedforeachdoor.Thiswillchangefromvehicletovehicleandneedstobecorrelatedtotestdata.Localcoordinatesystemswillbeneededfortheweatherstrips.Thefollowingcoordinatesystemshouldbeemployed:LocalX’ =OrientedwithdirectionofseallineLocalY’ =OrientedwithGlobalYLocalZ’=OrientedperpendicularwithbothlocalX’andlocalY’Theflexibledoormodelisthemostaccurateoneofthetwomodelingmethodsstatedhere.Itprovidesgoodrepresentationofbothrigiddoormodesandflexibledoormodes.Thisisespeciallyimportantforacousticanalysis.However,ittendstogeneratealargenumberofDOF’s,takesalongertimetomodel,andneedsmorecomputerresourcestorun.圖15車門詳細模型Fig15DoorDetailedModel前罩建模簡化模型，模型講解：前蓋應(yīng)仿照車門模型中所描述的相同的步驟進行建模。除了鉸鏈和鎖扣，通常在前罩的左前角和右前角有兩個垂直的凸起橡膠緩沖塊，可能還會有兩個側(cè)向的橡膠緩沖塊來緩沖側(cè)向的運動。當前罩要建立詳細模型或剛性模型時，這些橡膠塊應(yīng)該在局部坐標系內(nèi)建立零長度的彈簧單元模擬?？梢詫彌_塊的彈簧剛度進行調(diào)整，使分析模態(tài)結(jié)果與試驗結(jié)果保持一致。工程師可以使用以下典型的鉸鏈剛度值：KX=5.0×104牛/毫米，KY=1.0×104牛/毫米，kz=5.0×104牛/毫米。工程師可以使用以下典型的鎖扣剛度值：KX=1.0×104牛/毫米，KY=1.0×104牛/毫米，kz=1.0×104牛/毫米。工程師可以使用以下典型橡膠緩沖器的剛度值：KX=5.0x100牛/毫米，KY=5.0x100牛/毫米，kz=5.0x101牛/毫米。HoodModellingSimpleModel,ModelingNotes:Thehood/shouldbemodeledfollowingthesameprocedureforthedoorsasstatedinthedoormodel.Inadditiontothehingesandlatch,thereareusuallytwoverticalrubberbumpsbetweenthehoodandtheFESMatthefrontleftcornerandfrontrightcorner.Theremaybetwomorelateralrubberbumpstostabilizethelateralmotionofthehood.Whenthehoodismodeledasdetailedorrigidhood,thesebumpsshouldbemodeledusingzero-lengthCBUSHelementsandanappropriatelocalcoordinatesystem.ThestiffnessratesoftheCBUSHelementsshouldbetunedsothatthenormalmodesandFRF’softhehoodandFESMcorrelatewiththoseofhardwaretest.Theanalystmayusethefollowingtypicalhingestiffnessvalues:Kx=5.0x104N/mm,Ky=1.0x104N/mm,Kz=5.0x104N/mm.Theanalystmayusethefollowingtypicallatchstiffnessvaluesasastartingpoint:Kx=1.0x104N/mm,Ky=1.0x104N/mm,Kz=1.0x104N/mm.Theanalystmayusethefollowingtypicalrubberbumpstopstiffnessvalues:Kx=5.0x100N/mm,Ky=5.0x100N/mm,Kz=5.0x101N/mm.圖16前罩簡化模型Fig16HoodSimpleModel詳細模型，模型講解：前罩總成可分為兩組：白前罩（HIW）和前罩內(nèi)飾。白前罩(HIW)使用殼單元（shell）進行詳細的建模，內(nèi)飾部件采用集中質(zhì)量（conm2）和非結(jié)構(gòu)質(zhì)量建模。前罩鎖扣使用彈簧單元（CBUSH）來模擬，可以對彈簧剛度進行調(diào)整，使分析模態(tài)結(jié)果與試驗結(jié)果保持一致。分析師可以使用以下典型的鎖扣剛度值：KX=1.0×104牛/毫米，KY=1.0×104牛/毫米，kz=1.0×104牛/毫米。分析師可以使用以下典型橡膠緩沖器的剛度值：KX=5.0×100牛/毫米，KY=5.0×100牛/毫米，kz=5.0×101牛/毫米。DetailedModel,ModelingNotes:Allcomponentsofthehoodassemblyaredividedintotwogroups:Hood-in-white(HIW)andHoodtrim.EachHIWpartismodeledindetailusingshellelementsasindocument55-00-001.EachtrimpartismodeledusingeitherCONM2ornon-structuralmassasstatedinthisdocument.ThehoodlatchismodeledusingCBUSHelements.ThespringratesoftheCBUSHelementsshouldbetunedtotestdata.Theanalystmayusethefollowingtypicallatchstiffnessvaluesasastartingpoint:Kx=1×104N/mm,Ky=1×104N/mm,Kz=1×104N/mm.Theanalystmayusethefollowingtypicalrubberbumpstopstiffnessvalues:Kx=5.0x100N/mm,Ky=5.0x100N/mm,Kz=5.0x101N/mm.圖17前罩詳細模型Fig17HoodDetailedModel行李箱蓋建模簡化模型，模型講解：行李箱蓋應(yīng)仿照車門模型中所描述的相同的步驟進行建模。除了鉸鏈和鎖扣，通常在行李箱蓋的左后角和右后角有兩個垂直的凸起橡膠緩沖塊。當行李箱蓋要建立詳細模型或剛性模型時，這些橡膠塊應(yīng)該在局部坐標系內(nèi)建立零長度的彈簧單元模擬。應(yīng)該通過對模型的模態(tài)和頻率響應(yīng)與硬件測試關(guān)聯(lián)起來確定彈簧的剛度值。工程師可以使用以下典型的鎖扣剛度值：KX=1.0×104牛/毫米，KY=1.0×104牛/毫米，kz=1.0×104牛/毫米。工程師可以使用以下典型橡膠緩沖器的剛度值：KX=5.0x100牛/毫米，KY=5.0x100牛/毫米，kz=5.0x101牛/毫米。DecklidModellingSimpleModel,ModelingNotes:Thedecklidshouldbemodeledfollowingthesameprocedureforthedoorsasstatedabove.Inadditiontothehingesandlatch,thereareusuallytwoverticalrubberbumpsbetweenthedecklidandtheBIWattherearleftcornerandrearrightcorner.Whenthedecklidismodeledasdetailedorrigidhood,thesebumpsshouldbemodeledusingzero-lengthCBUSHelementsandanappropriatelocalcoordinatesystem.ThestiffnessratesoftheCBUSHelementsshouldbetunedsothatthenormalmodesandFRF’softhedecklidcorrelatewiththoseofhardwaretest.Theanalystmayusethefollowingtypicallatchstiffnessvaluesasastartingpoint:Kx=1.0x104N/mm,Ky=1.0x104N/mm,Kz=1.0x104N/mm.Theanalystmayusethefollowingtypicalrubberbumpstopstiffnessvalues:Kx=5.0x100N/mm,Ky=5.0x100N/mm,Kz=5.0x101N/mm.圖18行李箱蓋簡化模型Fig8decklidSimpleModel詳細模型，模型講解：行李箱蓋總成可分為兩組：白行李箱蓋（DIW）和行李箱蓋內(nèi)飾。白行李箱蓋(DIW)使用殼單元（shell）進行詳細的建模，內(nèi)飾部門采用集中質(zhì)量（conm2）和非結(jié)構(gòu)質(zhì)量建模。行李箱蓋鎖扣使用彈簧單元（CBUSH）來模擬，彈簧剛度應(yīng)按測試數(shù)據(jù)進行調(diào)整。側(cè)圍與行李箱蓋之間的密封條連接可以參考上面的車門密封條建立方法。正常的密封條總剛度值是3000牛/毫米，即每根彈簧的剛度是由車門彈簧總剛度除以總數(shù)量。工程師可以使用以下典型的鎖扣剛度值：KX=1.0×104牛/毫米，KY=1.0×104牛/毫米，kz=1.0×104牛/毫米。工程師可以使用以下典型的橡膠緩沖塊剛度值：KX=5.0×100牛/毫米，KY=5.0×100牛/毫米，kz=5.0X101牛/毫米。DetailedModel,ModelingNotes:Allcomponentsofthedecklidassemblyaredividedintotwogroups:Decklid-in-white(DIW)andDecklidtrim.EachDIWpartismodeledindetailusingshellelementsasindocument55-00-001.EachtrimpartismodeledusingeitherCONM2ornon-structuralmassasstatedinthisdocument.ThedecklidlatchismodeledusingCBUSHelements.ThespringratesoftheCBUSHelementsshouldbetunedtotestdata.Theweatherstrips/sealsbetweenbodystructureanddecklidshouldbemodeledasinthedoormodelingguildlines(asabove).Atypic