声学仿真及在工程中的应用

1FFT&MSCSoftwareConfidential声学仿真及在工程中的应用周泽声学仿真业务发展经理2015年5月27日2FFT&MSCSoftwareConfidentialActran软件及技术特点介绍3FFT&MSCSoftwareConfidentialActran主要模块•声学•振动声学•气动声学•TM•DGM•Etc.基于有限元方式Actran软件模块4FFT&MSCSoftwareConfidential声学仿真历史发展•21世纪前：边界元方式模型规模：x0,000•目前主流方式：有限元方式模型规模:x00,000tox0,000,000•发展方向：有限元：FEM&DGM模型规模x0,000,000tox00,000,000大规模问题，高频率问题5FFT&MSCSoftwareConfidential结构声和流致噪声•结构声：–由结构振动产生–外声场一般为纯声辐射问题–内声场一般为结构和声空间强耦合问题•流场噪声：–由流体湍流产生的噪声源：进排气噪声，风噪声，空调噪声•流场噪声源与结构耦合–流场噪声源作为结构振动的激励6FFT&MSCSoftwareConfidential频率域仿真和时间域仿真•频率域仿真：针对不随时间变化的现象，线性问题，计算频率响应函数和传递函数•时间域仿真，瞬态仿真：可针对瞬态随时间变化现象，非线性声学激励，发动机（动力总成）加速过程，冲击，碰撞现象等7FFT&MSCSoftwareConfidential机械行业噪声问题进气，排气旋转器械：风扇，涡轮增压器，压缩机等车辆机械驾驶舱GearBox动力装置EngineTurbochargerCoolingFanCompressorPumpHVACIntakeExhaust噪声8FFT&MSCSoftwareConfidential动力装置噪声辐射问题9FFT&MSCSoftwareConfidential声辐射仿真流程3.PostProcessingandAnalysis:Actran2.声学计算:ActraninFrequencyorTimeDomain1.振动计算：MSCNastran,Adams/Flex,Marc,Actran,etc.MapsStructuresurfacevibrationFRFWaterfallElementscontributionAcousticdirectivityTimedomainpressureSoundfileAnimation10FFT&MSCSoftwareConfidential声学模型建立•声学网格准备–振动体包络面:surfacewrapmeshofthevibratingstructure,formappingthestructurevibrationtotheacousticmesh.BoundaryConditionMesh,orBC_MESH–外部面网格：Exteriorinfiniteelementssurface:aconvexshape–体网格：VolumeelementsbetweenthetwosurfacesInfiniteElementsSurfaceInteriorsurfaceVolumeelements13P’P’’InfiniteElements11FFT&MSCSoftwareConfidentialPowertrainSoundRadiationwithActranSlidesextractedfromExperimentalValidationofanEfficientProcedureforLargeAcousticRadiationProblems,Gustafssonet.al.,ISMA201012FFT&MSCSoftwareConfidential•Thisproject:acompletetruckpowertrain,lengtharound2.5meters–Thestructurevibrationiscomputedwithastructuraltool•TheNastran,AbaqusandAnsysfilesarereadbyActran•SomeautomaticproceduresareavailablewithNastran–Theresults(velocitiesordisplacements)areusedastheexcitationoftheacousticradiationproblemsolvedbyActranProblem*P.T.=PowerTrain1m2013FFT&MSCSoftwareConfidentialComputationProcedureStructureComputationActranModel(w/ground)ActranResults14FFT&MSCSoftwareConfidential•BC_MESH:mapthestructureresultsontheacousticsurface•Procedureused:basedonintegration(moreadvancedtechnologythaninterpolation)–Thegeometriesmightbe(slightly)different–Themeshsizescanbeverydifferent(nolossofinformationfromFEA)–ThepenaltyonthesolverperformanceisweakStructuralResultsMappingActraninnersurfaceFEAoutersurface15FFT&MSCSoftwareConfidential•从振动结构表面创建声辐射需要的外部声学体网格1.填充结构表面的孔2.包络网格3.在原始网格基础上重新生成网格4.辐射网格（凸包和四面体网格组合），支持有无障板情况ACTRANVI集成网格工具-演示一个2MW风机齿轮箱Adams中风机多个部件的建模…ActranAPI16FFT&MSCSoftwareConfidential•Forthecompletesetoffrequency,regimesandmicrophones,amaximumof2dBdifferencehasbeendetected(marks:5dB)ExperimentalValidation17FFT&MSCSoftwareConfidential•Multiplesurfacescanbecreatedinordertomeasurethepowerradiatedbyeachpartofthepowertrain.SelectivePowerEvaluation18FFT&MSCSoftwareConfidential•AnalysisFlow–TransientResponseAnalysisbyAdams–LoadoneachnodewithatimehistoryistransformedtoOP2file–RadiationanalysisontheacousticspaceinActranmodelAdams与Actran联合：Adams2Actran转换器AdamsTimedomainsimulationAdamsStandardoutputConvertfromAdamsoutputtoOP2ActranTimedomainsimulationSPL(timedomain)Adams(Timedomain)TimedomainRadiationAdamstoActranToolkit19FFT&MSCSoftwareConfidential•EngineSlapSoundAnalysis–TheSoundfromcontactbetweenCylinderinnerwallandMovingPiston•duetokinematicmotion,thecontactpositionchangesfromtimetotime•contactforcewillcoursecrankcasevibration•Thecontactposition,forcesvariouswithenginerotationalspeedchange–FromAdams/Flexcouplinganalysis,motionandvibrationissimulated•asasoundsource,thevibrationresponseofthecrankcasesurfacecanbeobtained.EngineSlapSoundAnalysisFEMMODEL（Elastic）KinematicbehaviorForceduetocontactaxialloadduetokinematicmotionAdamsmodel20FFT&MSCSoftwareConfidentialEngineSlapSoundAnalysisTime-Frequency-PressureMap21FFT&MSCSoftwareConfidential•目标–实际机床的齿轮噪声•挑战–减小噪声•解决方法Solution齿轮噪声withcrowningandrelievingnocrowningandrelievingAdamsMachineryGearModelcrowningTiprelieving(1)啮合力(2)轴承力(3)箱体振动(4)声学辐射冠状齿轮和齿形修正使用Adams模拟多体运动，使用Actran预测噪声22FFT&MSCSoftwareConfidential齿轮噪声FFTFFT通过冠状齿轮和齿轮修正，啮合力减小了轴承力也减小了FFTStraightGearCrowningGear测点的声音也减小了23FFT&MSCSoftwareConfidential•噪声产生机理–电磁力由定子和转子运动产生–电磁力施加在定子及外部壳体上–定子和外部壳体振动产生声辐射电机噪声24FFT&MSCSoftwareConfidential与电磁软件联合仿真ActrancomputevibrationsastheacousticradiationComputethe3DmagneticfieldLoadstructuralmodelwithelectromagneticforcesComputeradiatednoisePressureatmicrophonesRadiatedpowerLocalindicatorGlobalindicatorActranContributionsanalysisOnradiatedpowerandSPL电磁软件25FFT&MSCSoftwareConfidential挑战随着新能源汽车的试用，电机噪声成为汽车噪声的新关注点解决方案通过电磁软件计算电磁力，并投射到Actran的结构网格上。Actran计算定子振动及其声学辐射价值将Actran嵌入电机噪声仿真流程，实现虚拟实验雷诺–电机噪声NoisecalculationprocessatRenaultRpmFrequencyNoiseateachengineorder(withtheWaterfalldiagramoutputbyActran)Numericalmethodologiestoaddresselectromagneticnoiseateachphaseofdevelopmentofelectricmachines,G.Fritz,Renault,H.Mechmeche,Laboratoired’Electrotechniqueetd’ElectroniquedePuissancedeLille,SIA2014(LeMan,France)26FFT&MSCSoftwareConfidential结构隔声量计算27FFT&MS