acoustics 2012

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1、ProceedingsoftheAcoustics2012NantesConference23-27April2012,Nantes,FranceNoisesourceidentificationtechniques:simpletoadvancedapplicationsK.B.GinnandK.HaddadBr¨uel&KjærSound&VibrationA/S,Skodsborgvej307,2850Nærum,Denmarkkevinbernard.ginn@bksv.com178123-27Apri

2、l2012,Nantes,FranceProceedingsoftheAcoustics2012NantesConferenceThenumberofnoisesourceidentification(NSI)techniquesavailabletoengineersworkingonnoise,vibrationandharshnessproblemshasincreasedconsiderablyinrecentyears.Thechoiceofthemostappropriatetechniquede

3、pendsupontheapplicationandtheinformationrequired.Thispaperreviewstechniquesfornoisesourceidentificationandquantificationrangingfromsimplehand-heldsoundintensitysystems,hand-heldarraysystemstolargegroundbasedmicrophonearrays.ThemethodsincludeBeamforming,Sphe

4、ricalBeamformingandAcousticHolography.Guidelinesaregiventohelptheengineerchooseasuitabletechniquebasedonthefrequencyrangeofinterest,thedistancefromthemeasurementarraytothetestobjectandtheresolutionrequired.Practicalapplicationexamplesrangingfromhearingaidst

5、owindturbinesarepresentedtoillustratethevariousNSItechniques.1IntroductionSincethe1980¶sthesoundintensitytechniquebasedonaphase-matchedpairofmicrophones,hasbeenusedtoNoisesourceidentification(NSI)techniquesareusedtomeasuretheacousticenergyflow.Thisyieldsnot

6、onlytheoptimisethenoiseemissionfromawiderangeofproductsamplitudebutalsothedirectionofthesoundenergy.Theincludingvehicles,householdgoodsandwindturbines.ThemethodhasbeenincorporatedintoanumberofgoalofNSIistoidentifythemostimportantsub-sourcesoninternationalst

7、andardstodeterminesoundpower.anobjectintermsofposition,frequencycontentandsoundSoundintensitymappinginvolvesthemeasurementofpowerradiation.Rankingofthesub-sourcescanthenbesoundintensityspectraatanumberofdiscretepointsonausedtoidentifywheredesignchangeswillm

8、osteffectivelygridclosetotheobjectundertest.Acontourplotisthenimprovetheoverallnoiseradiation.Withaconsiderableproducedandsuperimposedonaphotographtoenablenumberoftechniquesavailable,NVHengineersmighth