整车路面噪声与振动分析规范

Q/SZJ191001-2017整车路面噪声与振动分析规范SpecificationofVehicleRoadNoiseandVibrationAnalysis20XX20XX-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整车路面噪声与振动分析规范范围本标准规定了整车路噪分析的方法。本标准适用于CAE部门整车路噪分析。规范性引用文件无。术语和定义无。摘要Abstract当汽车在路面上行驶时，会经历宽频段的振动激励。最终振动激励传递到方向盘和座椅触摸到振动、传递到乘员耳朵听到声音、传递到后视镜看到摇晃。任何噪声或振动问题都有激励源和传递路径。噪声分为结构噪声和空气噪声。当振动源激励了轮胎、悬架和车身，在传递到车厢内声腔，这种噪声称为结构噪声。激励源之一是路面不平顺。不平顺可以用汽车经过的轮胎轨迹轮廓来描述，即功率谱密度PSD函数。整车路面响应分析是随机振动分析，具有线性、稳态和频域特征。在稳态随机过程中，随机变量（如：均值和变化量）统计值不随时间变化。线性稳态分析类似于整车路面模拟。一旦有可用的整车分析模型，路面响应分析的结果可以用来评估结构或子系统改变和接附点刚度变化对触觉、视觉、听觉或动态应力的影响。路面分析中包括两种分析（NASTRAN中）：第一种是单位加载；第二种是PSD加载。结构噪声分析属于第二种。在NASTRAN使用模态频率分析模块（SOL111）。Asavehicletravelsonaroad,itexperiencesabroadspectrumofvibrations.Thefinalmanifestationsofthesevibrationstypicallyoccurinthesteeringcolumnandseatastactilevibration,atthedriver’sandpassengers’earsasnoise,andattherear-viewmirrorasvisualvibration.Anynoiseorvibrationproblemhasanexcitationsourceandatransmissionpath.Dependingonthepathsthevibrationalenergytakesbeforereachingtheear,thenoiseisclassifiedasstructural-borneorair-borne.Whenthesourceexcitesthetires,thesuspensions,andthebodystructure,whichinturnexcitestheaircavityinthevehicle,thenoiseisstructural-borne.Onesourceofexcitationisfromroadroughness.Roughnessisdescribedbytheelevationprofilealongthetiretracksoverwhichthevehiclepasses.ThePowerSpectralDensity–PSDfunctionismostlyusedtorepresentroadroughness.Vehicleroadresponsearesimulatedwithrandomvibrationanalysis.Theanalysisislinear,stationary,andinthefrequencydomain.Inastationaryrandomprocess,thestatisticsoftherandomvariables(e.g.themeanandvariance)donotchangewithtime.Linearstationaryanalysisisausefulapproximationforvehicleroadsimulations.Onceavalidatedvehiclemodelisavailable,theresultsofroadresponseanalysesareusedtoevaluatetheeffectsofstructuralorsubsystemchangesorinterfacemountstiffnesstuningonthetactile,visual,aural,anddynamicstressresponse.Twoproceduresareusedforroadsimulationanalysis.Forthefirstprocedure,onlyadummyloadcaseisneededintheNASTRANfile.Forthesecondprocedure,alltheroadinputPSDinformationandresponseoutputsmustbesuppliedintheNASTRANfile.Theroadstructuralbornenoisesimulationprocedurealsobelongstothesecondprocedure.Inbothprocedures,modalfrequencysolution(SOL111)withCMStechniquesisperformedinNASTRAN.流程图无。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):Nastran后处理(Postprocessors):Hypergraph建模和分析过程Modeling/AnalysisProcedure路面轮廓RoadProfiles一旦路面类型和车速设定好，就可以得到适当的NASTRAN格式表格数据。这些是由测量的位移轮廓数据生成的。必须确保分析用的数据与测试对应。按照车速转换功率谱密度路面轮廓功率谱密度是与车速相关的函数。一般都有45英里/小时的功率谱密度数据，而分析车速可能是20英里/小时到60英里/小时。其转换公式如下：S(f)=(1/r)*S0*(f/r)其中，r=V/V0，S(f)是转换后功率谱密度、S0是转换前功率谱密度、V是转换后车速、V0是转换前车速、f是频率。Oncetheroadandvehiclespeedareselected,theappropriateNASTRANroadprofiletableneedstobeobtained.TheseNASTRANtablesaregeneratedfrommeasureddisplacementprofiles.Theusershouldalsomakesurethattheprofileisforthesamesegmentofroadusedinanytestingorevaluations.PSDConversionforVehicleSpeedTheroadprofilePSDisafunctionofvehiclespeed.SomeoftheoriginalbaselinePSDsarefor45mphvehiclespeed.Thesimulationspeedofthevehicleistypicallyintherangeof20to60MPH(e.g.30,35,40,45,50)ToconvertaroadprofilePSD(S0)atagivenspeed(V0)toacorrespondingprofilePSD(S)atanotherspeed(V),thefollowingformulacanbeused:S(f)=(1/r)*S0*(f/r)Wherer=V/V0,r>0,andf=frequencyinHz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无。坐标系CoordinateSystems无。建模技巧ModelingTechniques无。假设和限制Assumptions/Limitations无。载荷和边界条件Loads/BoundaryConditions约束唯一的约束是约束每个轮胎的接地点。也是路面激励的加载点。Theonlyboundaryconditiononthevehiclemodelisaconstraintoneachofthetirepatchpoints.Thisisdoneinconjunctionwiththeroadprofileloading.载荷第一步是加载单位正弦激励，可以建立传递函数矩阵；第二步是加载随机功率谱密度函数和相关正弦激励。Thefirststepistocreateloadcardstoapplysinusoidalloadsatallinputpointswiththeappropriatephaserelationships,etc.Thiscreatesthetransferfunctionmatrix(H).ThesecondstepistocreatecardsfortherandomPSDfunctionandassociatethesewiththesinusoidalloadcases.ThePSDs(S)arealreadysetupwiththeroadtables(TABRNDcardsandRANDPScards).TheusermustverifythatthesubcaseIDsontheRANDPScardsmatchthosetheusercreatedforthesinusoidalloads.结果Results结果格式ResultsFormats所有原始数据来自NASTRAN分析。对于毫米-吨-牛-秒单位制模型，功率谱密度单位是(mm/s^2)^2/Hz。响应的测量点在座椅内侧（一般四个安装点都会测）、方向盘12点和6点处。所有振动输出响应是自动功率谱密度加速度进行分贝处理，参考值为1(meter/sec^2)^2/Hz。输出值为均方根幅值。不过由于输入的路面激励值已经是均方根形式，因此就不需要进行转换了。要求输出峰值，NASTRAN卡片设置为PARAM,ACOUT,PEAK。AllrawresponsedatacomingfromNASTRANisinmodelunits.Foramm-Mg-N-smodel,thatwouldbeunitsof(mm/s^2)^2/Hz.Theresponsepointscalledoutinthetestprocedurearetherearinboardattachmentofthefrontseat(althoughallfourattachmentpointsareoftenused),steeringcolumn12O’clockand6O’clock.AlloutputresponseforvibrationaretheAUTO-PSDofaccelerationexpressedinDBreferencedto1(meter/sec^2)^2/Hz.TheoutputsareexpressedinRMSAmplitude.TheroadprofiletablesarealreadyinRMSamplitude;therefore,theuserdoesnotneedtoconverttheNASTRANoutput,andthePARAM,ACOUTshouldbeleftatthedefaultofPEAK相关测试CorrelationTests无。性能要求PerformanceRequirements无。分析要求ANALYSISREQUIREMENTS悬架衬套和悬置衬套参数有±15%变化内可使用。轮胎参数（模态坐标下的刚度和阻尼）可使用。静止轮胎与滚动轮胎的参数具体如何变化，还不是很清楚。但是从静止到滚动，轮胎模态频率一般会下降10%，甚至有的模态甚至是25%；而阻尼会翻倍，甚至三倍。减振器的阻尼（和刚度）要包括。内饰质量点（蓄电池和大灯）可以用±5%变化量。Suspensionbushingandpowertrainmountratevariationof+/-15%shouldbeused.Tireproperties(stiffnessanddampingofthemodalmasssystems)shouldalsobeused.Lessisknownaboutthevariationintirepropertiesbutknowledgeofhowthepropertieschangefromnon-rollingtorollingandthroughoutthespeedrangemaybeofuse.Thereistypicallya10%reductioninmodalfrequencyfromnon-rollingtorolling,withextremesofa25%reductionforsomemodes.Thedampingoftendoublesfromnon-rollingwithsomemodesincreasingbyafactorofthree.Shockdamping(andpossiblystiffness)mayalsobeincluded.Massoftrimmassitems(i.e.battery,headlamp,etc.)canbeusedprobablywitharangeof+/-5%.参考文件DOCUMENTATION无。联系人CONTACTS无。例子EXAMPLESSingleRoadandSpeedSOL111CEND$METHOD=1FREQUENCY=20$$STUD_DAMAGEDCONCRETEMPG(2000)RANDOM=85198$RCROSS(PHASE,NOPRINT,PUNCH,PSDF)=1000$SUBCASE1$INPUTSATRIGHTSIDETIRESFOR20MPHDLOAD=10SUBCASE2$INPUTSATLEFTSIDETIRESFOR20MPHDLOAD=15$BEGINBULK$$EIGENVALUEEXTRACTIONEIGRL1-1.250.021.0EIGRL11-1.300.021.0$FREQUENCYFREQ1,20,20.,1.0,180INCLUDE<model.bdf>$$EXCITATIONATTIREPATCHGRIDS:LHS$DLOAD101.01.0100121.0100131.0100141.0100151.0100161.0100171.0100181.0100191.010020$RLOAD1100121012110141120DISPRLOAD1100131012210142120DISPRLOAD1100141012310143120DISPRLOAD1100151012410144120DISPRLOAD1100161012510145120DISPRLOAD1100171012610146120DISPRLOAD1100181012710147120DISPRLOAD1100191012810148120DISPRLOAD1100201012910149120DISPSPCD10121546080131.SPCD10122546080231.SPCD10123546080331.SPCD10124546080431.SPCD10125546080531.SPCD10126546080631.SPCD10127546080731.SPCD10128546080831.SPCD10129546080931.$DELAY1014154608013.000000DELAY1014254608023.000676DELAY1014354608033.001351DELAY1014454608043.002027DELAY1014554608053.002702DELAY1014654608063.003378DELAY1014754608073.004053DELAY1014854608083.004729DELAY1014954608093.005404$$$$EXCITATIONATTIREPATCHGRIDS:LHS$DLOAD151.01.0150121.0150131.0150141.0150151.0150161.0150171.0150181.0150191.015020$RLOAD1150121512115141120DISPRLOAD1150131512215142120DISPRLOAD1150141512315143120DISPRLOAD1150151512415144120DISPRLOAD1150161512515145120DISPRLOAD1150171512615146120DISPRLOAD1150181512715147120DISPRLOAD1150191512815148120DISPRLOAD1150201512915149120DISPSPCD15121546090131.SPCD15122546090231.SPCD15123546090331.SPCD15124546090431.SPCD15125546090531.SPCD15126546090631.SPCD15127546090731.SPCD15128546090831.SPCD15129546090931.$DELAY1514154609013.000000DELAY1514254609023.000676DELAY1514354609033.001351DELAY1514454609043.002027DELAY1514554609053.002702DELAY1514654609063.003378DELAY1514754609073.004053DELAY1514854609083.004729DELAY1514954609093.005404$$TABLED1,120,,10.0,1.0,1000.0,1.0,ENDT$$$ROADPROFILE$$*********************************************************************$*$*NASTRANBASEDRIDEMETRICROADPROFILEDATA$*$*********************************************************************$$NOTE:DELAYcardmustmatchveh.speedforroadprofileselected.$Speedusedare20/25/35/45/55/60/65mph.$$RANDOMrrryy:rrr=RideMetricRoadNumber,yy=YearofMeasurement$=====================================================================$RANDOM85198$851(37.5mph)N&VRoadStudDamagedConcreteMPG1998$Processedfrom20mphdata$********************************************************************$Thedatainthetablesbelowisformillimetermodels.$********************************************************************$N&VRoadStudDamagedConcreteat20mphRANDPS85198111.00.0851981RANDPS85198221.00.0851982RANDPS85198121.00.0851983RANDPS85198120.0-1.0851984$TABRND1851981+0.4690.26E+000.9370.12E+011.4060.23E+011.8750.19E+01…+,ENDT$OutputrequestfortheAuto-PSDforsoundpressurelevelat$driversearposition(grid8500700)RCROSS,1000,DISP,8500700,1,DISP,8500700,1$ENDDATAMultipleRoadsand/orSpeedsSOL111CEND$METHOD=1FREQUENCY=20$RCROSS(PHASE,NOPRINT,PUNCH,PSDF)=1000$SUBCASE110$INPUTSATRIGHTSIDETIRESFOR20MPHDLOAD=10SUBCASE120$INPUTSATLEFTSIDETIRESFOR20MPHDLOAD=15$SUBCASE210$INPUTSATRIGHTSIDETIRESFOR35MPHDL