第9章-激光测振技术

激光测振技术ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter激光干涉基础111cos(2)EAftHSOE1E2222cos(2)EAft两束光波合成光波121122cos(2)cos(2)EEEAftAftShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter激光干涉基础光强分布121122cos(2)cos(2)EEEAftAft222222112cos(2)cos(2)IEAftAft11222cos(2)cos(2)AftAft12121212cos(4)cos()AAftAA22222112cos(2)cos(2)AftAft低频分量，且与物体表面的状态有关ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter激光测量的类型激光全息方法云纹干涉电子散斑干涉技术（ESPI-ElectronicSpecklePatternInterferometry）激光多普勒测振激光位移测量的方法，都是通过处理和分析物体表面与参考面在变形前后的位相变化、光强变化等，从而实现高精度的振动位移测量。ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter时间平均全息方法1965年由Powell提出。可以测量和分析物体的微幅振动。对于在某一稳定频率下作简谐振动的物体，用连续激光照射，并在比振动周期长得多得时间内在全息干板上曝光，客在物体表面所反射的光与未作位相调制的参考光相叠加，将两束光记录在干涉图记录在全息干板上。其再现的图像由反映节线和等振幅线组成的干涉条纹来表示振幅分布。这就是时间平均全息方法的测振原理。ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter激光束物体全息干板,Vxy12现常用方法：激光频闪照明多脉冲激光器ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter激光多普勒效应VfD2ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterL4BSXRXMVfD2MichelsonDMRMRfRIIKRIItI2cos2ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterDBMRMRffRIIKRIItI2cos2BraggCell：声光调制器，在40MHz或更高的驱动频率下引入载波信号ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter信号处理ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterLDV激光测振仪的类型ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter1.激光多普勒振动测量技术的特点测量定义：光学粗糙表面物体振动速度或振幅在激光束方向上的投影分量。表面形状引起的位移量被视为背景噪声。Laserbeam2.特点：V非接触,无附加质量影响抗干扰能力强,可现场应用极大的动态范围和高精度频率:DCto20MHZ速度:1µm/sto30m/s加速度:1,000,000g以上振幅:0.1um(100KHz)to10mabove测量方便快捷ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneter特殊应用：轻巧，柔性或微型结构高温，腐蚀，放射，高压等恶劣环境大型构件整体大振幅，高g值振动，冲击极低频或极高频振动ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterPrincipleofOperationandApplicationsThisPowerpointpresentationinformsyouaboutoperationofthePolytec’sScanningVibrometerPSV-300andpresentssometypicalmeasurementscarriedoutintheautomotiveindustry.AsthismaterialcontainsseveralAVImoviefilesafastCDROMisrecommendedforviewing.PolytecScanningVibrometerPSV-300ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterVibrometerControllerOFV-3001DataManagementSystemwithNTWorkstationScanElectronicsVideoVibrometerSensorOFV-303ScanningMirrorsBasicConfigurationofaScanningVibrometerThePSV-300comprisesanopticalscanningheadincorporatingthelaserinterferometersensor,beamsteeringopticsandavideocamera.DatafromthescanningheadareprocessedbytheOFV-3001vibrometercontroller.AWindowsNTworkstationisresponsibleforscanpointdefinition,dataacquisitionandcontroloftheentiresystem.PolytecScanningVibrometerPSV-300SensorHeadOFV-056TestobjectShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterTheOFV-056SensorHeadfeatures:PolytecScanningVibrometerPSV-300Scanangle40x40degreeswith0.02degreesresolution.Importantfeatureformeasurementsoflargeobjectsinlimitedspaceareas72xzoomcolorvideocameraformeasuringlargeand/orsmallobjectswithoutre-positioningthesensorhead.Videocamera,laserfocus,rangesettings:Allremotecontrolledforeasyoperation,e.g.withthescanheadinstalledinanenginetestchamber.Largerangeofworkingdistance0.2mto50mCoaxialattachmentforscanningsmallobjectsdownto1x1mm,e.g.injectornozzlesShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterPSV-300-HDataManagementSystemdesignedforthespecificneedsofourautomotivecustomersPolytecScanningVibrometerPSV-3006velocityrangesupto10m/s.Importantformeasurementsontires,shaftsandotherrotatingparts.4channeldataacquisitionwith80kHzbandwidth.Upto3referencechannelsarerecordedtogetherwiththevibrometerdata.FullremotecontrolofallhardwareScanningspeedupto100pointspersecond,reducingthebrakesquealmeasurementtimeBuild-inmultiplechannelsignalgeneratorOptionalordertrackingsoftwareforrun-upmeasurements.ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterPolytecScanningVibrometerPSV-300DefineScanAreaAdjustParametersSelectScanModeScanSelectFrequencyBandsPresentationofDataExportMakingaPSVmeasurementOnthefollowingpageswewilldemonstratehoweasyaPSVmeasurementisset-upandcarriedout.TheexperiencedPSVusermayuseournewVisualBasicMacrofeaturetogeneratehisownmacrosforautomationoftheentiremeasurementroutine.ShanghaiJiaotongUniversity-EngineeringMechanicsExperimentalCeneterPolytecScanningVibrometerPSV-300DefineScanAreaAdjustParametersSelectScanModeScanSelectFrequencyBandsPresentationofDataExportLikeinadrawingprogramtheuserdefinesthescanpointsonthestructure.Differentobjectsmayhavedifferenttypesofmeshesandmeshdensities.Singlepointscanbedefinedaswellaslinesofpoints(e.g.forscanningadriveshaft)withde