Q/SZJ191001-2017聲腔建模和模態(tài)分析規(guī)范SpecificationofModelingandModalAnalysisForAcousticCavity20XX20XX-09-30實(shí)施20XX-08-28發(fā)布XXXX汽車(chē)工程技術(shù)有限公司發(fā)布Q/SZXX-X-2017聲腔建模和模態(tài)分析規(guī)范范圍本標(biāo)準(zhǔn)規(guī)定了術(shù)語(yǔ)和定義、聲腔建模和模態(tài)分析方法及結(jié)果處理方法。本標(biāo)準(zhǔn)適用于CAE部門(mén)的聲腔建模和模態(tài)分析。規(guī)范性引用文件無(wú)。術(shù)語(yǔ)和定義無(wú)。摘要Abstract本文描述聲腔建模和模態(tài)分析規(guī)范。噪聲問(wèn)題通常分為兩類：空氣噪聲：如輪胎發(fā)出的輻射噪聲，排氣和動(dòng)力系統(tǒng)產(chǎn)生的噪聲。結(jié)構(gòu)噪音：道路來(lái)源（如在粗糙的道路上產(chǎn)生的振動(dòng)通過(guò)底盤(pán)懸掛系統(tǒng)傳輸?shù)杰?chē)身）；動(dòng)力總成的來(lái)源（如發(fā)動(dòng)機(jī)振動(dòng)通過(guò)懸置傳遞到車(chē)身系統(tǒng)）；傳動(dòng)系統(tǒng)的來(lái)源（通過(guò)差分傳輸如扭轉(zhuǎn)振動(dòng)安裝系統(tǒng)）。這個(gè)過(guò)程涉及建立一個(gè)結(jié)構(gòu)聲學(xué)系統(tǒng)模型的結(jié)構(gòu)。僅傳播噪聲問(wèn)題。我們可以把這個(gè)建模任務(wù)分為3個(gè)不同的部分：簡(jiǎn)化車(chē)身內(nèi)飾模型。創(chuàng)建聲學(xué)腔。創(chuàng)建耦合文件。ThisspecificationdescribesthemodelingandmodalanalysismethodofAcousticCavity.Noiseconcernsaretypicallydividedintotwogroups:Airbornenoise,suchasradiatednoisefromthetire,exhaustandpowertrain.Structure-bornenoisefrom:Roadsources(egroughroadshaketransmittedintothebodyviathesuspension);Powertrainsources(egenginevibrationstransmittedintothebodyviathemountingsystem);Drivelinesources(egtorsionalvibrationstransmittedthroughthedifferentialmountingsystem).Thisprocedureisconcernedwiththecreationofastructuralacousticsystemmodelforstructurebornenoiseproblemsonly.Wecandividethismodelingtaskinto3distinctsections:Preparingthetrimmedbodymodel.Creatingtheacousticcavities.Creatingthecouplingfile.流程圖ProcessFlowDiagram創(chuàng)建創(chuàng)建聲腔模型Creatingtheacousticcavities設(shè)置邊界條件SettheboundaryConstraints提交計(jì)算NastranSOL103RunNastranSOL103輸出位移和動(dòng)畫(huà)振型OutputDisplacementsandAnimateModeShapes優(yōu)化Optimization結(jié)果是否滿足要求？IstheresultOK？評(píng)價(jià)標(biāo)準(zhǔn)Evaluationstandard結(jié)束EndNo圖1流程圖Fig1ProcessFlowDiagram工具描述ToolDescription仿真分析過(guò)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(guò)程Modeling/AnalysisProcedure所有的模型必須符合NVH建模標(biāo)準(zhǔn)，以及符合噪聲和振動(dòng)分析的建模文檔。AllmodelsmustconformtotheNVHmodelingstandardsasoutlinedaswellastheindividualcomponentmodelingdocumentsasapprovedbytheNoiseandVibrationFocusGroup.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(zhǎng)度(Length) 毫米(mm)時(shí)間(Time) 秒(Second)內(nèi)容Contents內(nèi)部的乘客車(chē)廂空腔定義的邊界概述：BIW（白車(chē)身）結(jié)構(gòu)、固定玻璃（前后擋風(fēng)玻璃）、車(chē)門(mén)帶玻璃、座椅控制臺(tái)和儀表板、行李箱蓋和/或后擋板。內(nèi)腔通常分為以下子腔：內(nèi)腔內(nèi)部、前座椅、后座椅、行李箱蓋/行李箱–包括一個(gè)備胎部分、IP控制臺(tái)、門(mén)的內(nèi)部空腔。這些空腔之間耦合是通過(guò)：共享相同的邊界網(wǎng)格，創(chuàng)建流體耦合。Theinteriorpassengercompartmentcavityisdefinedbytheboundaryoutlinedby:TheBIW(body-in-white)structure、Fixedglass(frontandrearwindshield)、Doorswithglass、Seats、Consoleandinstrumentpanel、Decklidand/ortailgate.Theinteriorcavityisusuallysub-dividedintothefollowingsub-cavities:Cabin–Interior、Seats–Front、Seats–Rear、Decklid/Boot–Whichincludesasub-divisionforthesparewheel、IPConsole、Doors-Internalcavities.Couplingbetweenthesecavitiesisenabledbyeither:SharingidenticalboundinggridsorCreatingfluidtofluidcoupling.圖2聲腔Fig2InternalAcousticCavities結(jié)構(gòu)聲學(xué)分析空氣的兩種材料特性是必需的:質(zhì)量和密度，聲音在空氣中的聲速。這些屬性取決于環(huán)境溫度、氣壓和濕度。結(jié)構(gòu)聲學(xué)分析，濕度的影響被忽略。使用空氣屬性為標(biāo)準(zhǔn)大氣壓力。結(jié)構(gòu)聲學(xué)分析的標(biāo)準(zhǔn)溫度是23攝氏度。空氣，體積模量計(jì)算的方程:Forstructuralacousticsanalysis,twomaterialpropertiesofairarerequired:themassdensityof，airandthespeedofsoundinair.Thesepropertiesdependupontheambienttemperature,airpressureandhumidity.Forstructural.acousticsanalysis,theeffectsofhumidityareignored.Usetheairpropertiesforstandardatmosphericpressure.Thestandardtemperature.forstructuralacousticsanalysisis23oC.thebulkmodulusofair,whichiscalculatedbytheequation:在MSC／NASTRAN、空氣屬性用mat10卡指定，以下腔特性適用于不同的腔體網(wǎng)格。InMSC/NASTRAN,theairpropertiesarespecifiedontheMAT10card.shouldbeappliedtothedifferentcavitymeshes.表1聲腔材料參數(shù)Table1AcousticCavitiesmaterialparameter坐標(biāo)系CoordinateSystems分析采用整車(chē)坐標(biāo)系。Analysisusevehicleglobalcoordinatesystem.建模技巧ModelingTechniques請(qǐng)RefertotheAcousticCavitymodelingguidelines.假設(shè)和限制Assumptions/Limitations無(wú)。載荷和邊界條件Loads/BoundaryConditions約束：自由狀態(tài)，0-200Hz。Noconstraints,0-200Hz.加載：無(wú)。Loads：N/A結(jié)果Results輸出位移及振型云圖。聲腔模態(tài)分析應(yīng)在MSC／NASTRAN進(jìn)行驗(yàn)證模型。聲學(xué)固有頻率和振型應(yīng)與試驗(yàn)數(shù)據(jù)進(jìn)行比較?？涨还逃蓄l率可以根據(jù)理論公式推算，空腔內(nèi)部假設(shè)成車(chē)廂是長(zhǎng)方形的盒子。車(chē)廂前/后尺寸通過(guò)估計(jì)確定粗略距離，從駕駛室的前部到皮卡車(chē)、后車(chē)門(mén)或廂式車(chē)的后地板，汽車(chē)燈（轎跑車(chē)或轎廂）的距離為縱向尺寸。橫向尺寸指門(mén)內(nèi)面板之間的大概距離確定尺寸。垂直尺寸指頂蓋到地板之間的大概距離。A型腔固有頻率的計(jì)算公式如下：OutputDisplacementsandModeShapes.NormalmodesanalysisofthecavitymodelshouldbeperformedinMSC/NASTRANtoverifythemodel.Theacousticnaturalfrequenciesandmodeshapesshouldbecomparedtotestdataifavailable.Cavitynaturalfrequenciescanbeestimatedbyassumingthattheinteriorcavityofthepassengercompartmentisarectangularbox.Thefore/aftdimensionisestimatedbydeterminingthedistancefromthefrontofdashtothebackpanelofapickup,reardoorsofavanorutilityvehicle,orbacklightofacar(coupeorsedan).Thelateraldimensionisestimatedbydeterminingthedistancebetweenthedoorinnerpanels.Theverticaldimensionisestimatedbydeterminingthedistancebetweentheroofandfloor.Theformulaforcalculatingthecavitynaturalfrequenciesofarectangularboxisgivenbelow:下面是一些例子用于指定i,j,k:Belowaresomeexamplesforspecifyingi,jandk:1stFore/AftMode=>i=1,j=0,k=02ndFore/AftMode=>i=2,j=0,k=01stLateralMode=>i=0,j=1,k=0下面的例子根據(jù)理論公式計(jì)算空腔振動(dòng)頻率BelowaresomeexamplesforcalculatingestimatedcavityresonantfrequenciesfortheM-Van:Lx=3.67m1stFore/AftMode,F(1,0,0)=47.3HzLy=1.64m1stLateralMode,F(0,1,0)=