用于损伤检测的新型低声阻抗传感器.pdf

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1、ShanghaiJiaoTongUniversityUniversityofMichigan-ShanghaiJiaoTongUniversityJointInstituteNovellowacousticimpedance(LAI)transducerfordamagedetectionByAliMohammadabadiAthesissubmittedinsatisfactionoftherequirementsforthedegreeofMasterofScienceinMechanicalEngineeringatShanghaiJiaoTongUniversityCommitt

2、eeincharge:ShanghaiProf.RobertoDugnani,ChairJuly,2014Prof.ShaneJohnsonProf.SungLiangChen万方数据万方数据上海交通大学交大密西根学院用于损伤检测的新型低声阻抗传感器AliMohammadabadi上海交通大学密西根学院硕士学位论文机械工程专业委员会成员：上海RobertoDugnan（主席）2014年7月ShaneJohnson陈松良万方数据万方数据万方数据AbstractThemanufacturingandvalidationofanovelLowAcousticImpedance(LAI)ispr

3、esentedinthisresearch.TheproposedsystemreliesonanactivepiezoceramicPZT(Lead-Zirconate-Titanate)transducer,aswellasanI/Oelectroniccircuitandsoftwareareusedtoexcitethetransducerandmonitoritsresponse.ThebehaviorofthePZTtransducercanberelatedtothemechanicalimpedancechangesofthetargetstructure.Sinceth

4、epresenceofdefectsaffectsthelocalmechanicalresponseofthetargetstructure,thedefectscanbedetectedbymonitoringchangesinthestructure’simpedancewiththePZTtransducer.Inthefirstpartofthethesis,variouscommonNon-DestructiveEvaluation(NDE)techniquessuchasultrasound,x-rayandthermographyarereviewedandthefund

5、amentalphysicalelectro-mechanicalbehaviorofpiezoelectrictransducersisalsointroduced.TheLAItechniquefundamentals,featuresandadvantagesarediscussed.Thedetaileddescriptionofthedesignandfabricationoftheproposedsystemincludingatransducer,theI/Oelectronics,andcontrollingsoftwareisprovided.Finally,theex

6、perimentalresultsandnumericalmodelsareintroducedtoverifytheeffectivenessoftheproposedsystemandtransducers.Theverificationisdonebydifferentfiberglass–epoxycomposites,woodenandpolymerspecimens.TheLAItechniqueprovedtheabilityofdefect’sdetectionsuccessfully.Forexample,thetechniquehasbeentestedonfiber

7、glass-epoxycompositeplateswhichhavebeensubjectedtoimpactbydropweightimpactorandthenormalizedimpedancevalueshavebeenpresentedinlineandsurfaceplots.Inthecaseofcompositeplates,thetechniquecoulddetectthepresenceandapproxim