1、南京航空航天大學(xué)碩士學(xué)位論文損傷復(fù)合材料梁結(jié)構(gòu)中蘭姆波的反射與透射研究姓名：袁晚春申請學(xué)位級別：碩士專業(yè)：工程力學(xué)指導(dǎo)教師：周麗20070101損傷復(fù)合材料梁結(jié)構(gòu)中蘭姆波的反射與透射研究iiABSTRACTSincestructuralhealthmonitingusingLambwavehasbeenwidelyemployedinaerospacelargecivilstructuresitissignificantlyimptan

2、ttodevelopatheytomodetheLambwavepropagationbehaviourindamagedstructures.InthisstudyLambwavepropagatingincompositebeamsarefirstmodelledanalyticallyusingbothhigherderbeamtheyelasticitybeamtheythedispersionrelationsofthewav

3、esareestablished.ComparingtheresultsofthetwoanalyticaltheiesfindsoutthatthelowermodessuchasA0S0arematchedwellinthewholefrequencydomainthehighermodessuchasA1S1areapproximatelyclosedinthelowerfrequencydomain.Baseonthesewav

4、epropagationinbeamscontainingdamagesuchasinhomogeneitydelaminationisstudied.WhenthepropagatingLambwavereachthedamagepositionitwillpartiallyreflectsbackintotheundamagedregionpartiallytransmitsintothedamagedregionofthebeam

5、alsothereisamodeconversionbetweeneachLambmode.Ftheinhomogeneitythedifferentdamagedegreeisresearchedtofindoutthedifferentwavereflectiontransmissioncoefficients.Fthedelaminationtwoextremecases:noncontact(open)fullycontact(

6、closed)delaminationareconsideredtoexaminethewavereflectiontransmission.Inadditionpowerflowascalardeionofenergyreflectiontransmissiontogetherwithmodeconversionofenergyisvariedwithdifferentdamagedegreedamageposition.Meanwh

7、ileafiniteelementmethodisemployedtosimulatethewavepropagationinthedamagedbeamresultsshowthatitiscoincidedwiththeanalyticalmethodwhichverifiesthevalidityoftheanalyticalmethod.thisprovidesanefficienttheyfinitiativemonittec

8、hnology.ThisresearchispartiallysupptedbytheNationalNaturalScienceFoundationofChinaunderGrantNo.50478037No.10572058theResearchFundftheDoctalProgramofHigherEducationunderGrantNo.20050287016.Keywds:Lambwavestructuralhealthm