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1、重庆大学硕士学位论文II英文摘要ABSTRACTWiththerapiddevelopmentofindustrialtechnology,therequirementsforengineeringapplicationmaterialpropertiesarebecomingincreasinglyhigher.Compositeiswidelyusedinindustrialfieldbecauseoftheadvantageofhigherstrength,biggerelasticitymodulusandlighterquality.
2、Thehealthofcompositestructuresisdirectlyrelatedtotheintegrityandsecurityofsystem.Inthecompositelaminates,themostcommondefectsarefiberbreakage,matrixcrack,anddelaminationandthemostdifficultforexaminationistheinternaldelamination,andthisdefectseriouslyaffectsthecharacteristics
3、ofthecompositematerial.Meanwhile,itbearssafetyrisksduringitsusage.Therearemanylargeaccidentsmadebydelaminationinhomeandabroad.Therefore,delaminationexaminationtothecompositematerialisverysignificant.ThispaperusingLambwavetoexaminedelaminationdefects,analyzingthepropagationpr
4、incipleofLambwaveinthecompositeandconductingfiniteelementsimulation,usingthetimereversalmethodandwaveletanalysismethodtoachievefreebaselinepurpose,anddisplayingcompositedelaminationdefectsintwo-dimensionalimageaccordingtoprobabilityimaging.Firstly,thispaperstudiespropagation
5、theoryequationandthedetectingprincipleofLambwaveinthecompositeplate,obtainsthedisperseequation,drawsoutthedispersioncurves,makesthedetailedtheoreticalanalysisaboutthetimereversalmethod（TRP）,andestablishesfreebaselinedelaminationexaminationbasiswithTRPprincipleandwaveletanaly
6、sismethod.Byanalyzingthefocusingsignalaftertimereversalprocessingandcomparingthedifferencebetweentheoriginalinputsignalsandfocusingsignal,weproposetime-reversefocusedpropertyevaluationindexesaboutthefocusingsignalsandwaveletothernesscoefficientevaluationindexes,andtheywillbe
7、usedasanimportantparameterinimagingdamageinthefollowingsection.Basedonthestudyabouttheorymethod,byusingthefiniteelementanalysissoftwareABAQUS,webuildthepropagationmodelofLambwaveincompositeplate,thencarryoutdeepstudyonthepropagationcharacteristicsofguidedwavesontheIII重庆大学硕士学
8、位论文one-dimensionalLinepropagationmodelandtwo-dimensionalPlanepropagationmod
