噪声和振动的声学灵敏度分析规范

Q/SZJ191001-2017噪声和振动的声学灵敏度分析规范SpecificationofAcousticSensitivityAnalysisforNoiseandVibration20XX20XX-12-31实施20XX-11-27发布XXXX汽车工程技术有限公司发布Q/SZXX-X-2017噪声和振动的声学灵敏度分析规范范围本标准规定了术语和定义、噪声和振动的声学灵敏度分析方法及结果处理方法。本标准适用于CAE部门的噪声和振动的声学灵敏度分析。规范性引用文件无。术语和定义无。摘要Abstract声学灵敏度是指单位激励作用在底盘与车身连接点时，车内人耳处测量的声压级，即接受点声压与输入点激励力(P/F)的比值。声学灵敏度能够反应车身板件的正负贡献量，振动源通过底盘传到车身，再引起车身板件的振动，从而产生噪声，噪声再通过空气传到乘员的耳朵。这种类型的分析是一个简单的谐波响应。AcousticsensitivityismorecommonlyknownastheP/Fbecauseitisthefrequencyresponsefunctionforthesoundpressure(P)inthepassengercompartment,duetoaforce(F)appliedtothestructure.Theacousticsensitivitygivesameasureofhowmuchthevehiclebodyisamplifyingorattenuatingtheenergyasitflowsfromastructuralinput,intotheacousticfluid,andtothepassenger.Thistypeofanalysisisasimpleharmonicresponse.

流程图ProcessFlowDiagram收集详细模型收集详细模型(内饰车身和声腔模型)CollectDetailedModels(TrimmedBodyandAcousticCavity)设置边界条件和载荷SettheboundaryConstraintsandLoad提交计算NastranSOL108输出X向位移（声压）OutputXDisplacements优化Optimization结果是否满足要求？IstheresultOK？评价标准Evaluationstandard结束EndNo结果后处理（HyperGraph）图1流程图Fig1ProcessFlowDiagram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或OptiStruct后处理(Postprocessors):Hyperview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声学模型应包括：声腔模型和白车身。开闭件、底盘、内饰件等主要的部件。详细的开闭件模型都应该包含在内，这些封闭的腔体对声学灵敏度影响很显著，不紧对低频有影响，对高频也有很大影响。根据分析类型车架和副车架都应包括在内。如果关注动力总成悬置系统的声学灵敏度，就需要连接车架和副车架，这样力就可以通过接附点进行传递。如果关注的是车身与车架的连接界面，那么就应该把车架去掉，只关注车身。Themodelforthisprocedureshouldinclude:acousticcavityandbody.Optionally,detailedclosuresmaybeused,andframesandcradles/crossmembersmaybeincluded.Thedetailedclosuresshouldalwaysbeincludedwhenpossible.Theaffectsoftheseclosuresontheacousticresponseofthesystemcanbesignificantfornotonlylowfrequency(boom)buthigherfrequencyphenomena.Framesandcradlesshouldbeincludeddependingonthetypeofanalysisbeingconducted.If,forinstanced,theconcerniswiththeacousticsensitivityofthepowertrainmountingsystem,theframeorcradleswillneedtobeattached,suchthattheforcescanbeappliedtothepowertrainmountinglocations.Iftheconcerniswiththeinterfacebetweenthecradleandthebody,thecradleshouldberemovedtolookatonlytheperformanceofthebody.结构声腔响应分析需要几个特殊的参数。首先，两个特征值提取卡片（eigrl），结构声腔分析指定一个，流体声腔指定一个，这是因为，MSCNastran计算时这个两个需要分别设置。如果当残余向量不输出，流体的特征值提取频率范围要增大到结构频率的两到三倍。还需要阻尼卡片，一个是结构阻尼，一个是流体阻尼。G，GFL可以用于结构阻尼。，如果没有特定的阻尼信息，结构阻尼和流体阻尼取3-4%。使用求解器SOL108，只能使用阻尼参数G和GFL,残余向量不需要输出。分析输出每个乘员的外耳声压。Theanalysisforastructuralacousticresponsetakesafewspecialparameters.First,twoEIGRLcardsandtwoMETHODcardsareneeded.OneMETHODcardshouldbedesignatedforstructurewith“METHOD(STRUCTURE)”,andoneforthefluidwith“METHOD(FLUID)”.ThisisbecauseMSCNASTRANcalculatesthesetwomodalsetsseparately.TheEIGRLcardforthestructurecangouptothemaximumfrequencyofinterest,butonlyifPARAM,RESVEC,YESisspecified(seetheharmonicresponseprocedurefordetails).IfRESVECisnotturnedon,theEIGRLcardmustextendtoafrequencyatleasttwicetothreetimesashighasthemaximumfrequencyofinterest.TwoSDAMPINGcardsarealsorequired;oneisforthestructure,andoneisforthefluid.Theyarealsodesignatedby“SDAMPING(STRUCTURE)”,and“SDAMPING(FLUID)”.Alternately,PARAM,GandPARAM,GFLcanbeusedtoforstructuraldamping.Ifnospecificmodaldampinginformationisavailable,valuesof3-4%ofcriticalforthefluidandstructureshouldbeused.IfaSOL108directsolutionisused,onlyPARAM,GandPARAM,GFLcanbeused.Also,PARAM,RESVECisnotneededinthatcase.Theoutputfortheseanalysesshouldbethegridsattheeachofthepassengers’earlocations.坐标系CoordinateSystems分析采用整车坐标系。Analysisusevehicleglobalcoordinatesystem.建模技巧ModelingTechniques请RefertotheAcousticCavitymodelingguidelines.假设和限制Assumptions/Limitations无。载荷和边界条件Loads/BoundaryConditions除了相关Theboundaryconditionsshouldbefreeforallsituationsexceptcorrelationstudies.Forcorrelationstudies,oftenthefreeboundaryconditionwillwork,however,insomeinstances,modelingtheisolatorpadsthatwereusedinthetestsmaybeimportant.单位载荷（1N）应用到每一个加载点，一个点X、Y、Z三个方向。每个加载点每个方向都是独立的一个工况。因此，对于4个弹簧座的动力系统，就应一共有12个工况。如例所示。这些荷载是单位荷载。因此，该模型的输出是牛/平方毫米或者兆帕。输出模型是线性的，非加权数据。后处理转化为分贝或A计权。这些后处理的数据可被用于多个分析研究。Thereshouldbeoneunitload(1N)appliedtoeachloadgridandeachdirection.Eachloadshouldbeindependentofeachotherload.Therefore,forapowertrainsystemwithfourmounts,thistranslatestotwelvedifferentsubcases.Thesubcasesshouldbesetupasshownintheexamplesection.Theseloadsshouldbeunitloads.ThustheoutputofthemodelisN/mm2ormPa.Theoutputofthemo