壓電陶瓷反平面裂紋問題中的電場梯度效應.pdf

1、華中科技大學碩士學位論文壓電陶瓷反平面裂紋問題中的電場梯度效應姓名：曾云申請學位級別：碩士專業(yè)：固體力學指導教師：胡元太20050425IIAbstractDuetotheirintrinsicelectromechanicalcouplingbehavispiezoelectricmaterialsareusedwidelyinhightechnologicaldevicessuchastransducerssenssultrason

2、icgeneratsactuats.Howeverwhensubjectedtoelectricmechanicalloadsthesepiezoelectricmaterialscanfailprematurelyduetotheirbrittlenessthepresenceofdefectsflawssuchascavitiescracksdislocations.Therefeitisimptanttoinvestigateth

3、eelectroelasticinteractionfracturebehaviofpiezoelectricmaterials.Becausethetransverselyisotropicpiezoelectricceramicsarethemostprevalentintheactualapplicationareasofindustryengineeringtheresearchontheantiplanefracturebeh

4、aviofpiezoelectricceramicshasbeenveryactiveinrecentyears.Inthisdissertationanantiplanecrackprobleminpiezoelectricceramicsisanalyzedwiththetheyfelectroelasticsolidsincludingelectricfieldgradienteffectsi.e.theelectricfield

5、gradientthey.Firstthederivationoftheelectricfieldgradienttheyisintroducedincludingtheconstitutiveequationstheboundaryconditions.Afterthistheelectricfieldgradienttheyisusedtosolvethepiezoelectricantiplanecrackproblem.Four

6、iertransfmisemployedtoreducetothismixedboundaryvalueproblemtothreepairsofdualintegralequationsalsothenewadditionalboundaryconditionsarediscussed.ByusingtheCopsonmethodoneoftheseequationsistransfmedintoaFredholmintegraleq

7、uationofthesecondkindtoobtainthesolution.Furthermetheintensityfactsthetotalenergyreleaseratethemechanicalstrainenergyreleaserateareobtainedcomparedwiththeclassicalresultswithoutconsideringtheelectricfieldgradienteffects.

8、FinallyusingPZT5Hasanumericalexampletheinfluenceoftheelectricfieldgradienteffectonpiezoelectricfracturemechanicsisexamined.Keywds:PiezoelectricceramicsAntiplanecrackElectricfieldgradientFouriertransfmIntensityfactsTotale