壓電陶瓷反平面裂紋問題中的電場梯度效應(yīng).pdf

1、華中科技大學(xué)碩士學(xué)位論文壓電陶瓷反平面裂紋問題中的電場梯度效應(yīng)姓名：曾云申請學(xué)位級別：碩士專業(yè)：固體力學(xué)指導(dǎo)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