層合板接頭損傷失效與疲勞壽命研究.pdf

1、南京航空航天大學(xué)博士學(xué)位論文層合板接頭損傷失效與疲勞壽命研究姓名：王丹勇申請學(xué)位級別：博士專業(yè)：航空宇航推進(jìn)理論與工程指導(dǎo)教師：溫衛(wèi)東20060401層合板接頭損傷失效與疲勞壽命研究IIABSTRACTMechanicallyfastenedjointsofcompositematerialsaremainlycomponentsinaircraftstructureswhichneedtobesubjectedtostaticload

2、ingsfatigueloadingsduringwking.Thepredictionofdamagefailurefatiguelifeisoneofquestionsthatdesignersalwayspayattentionto.Indertoadequatelyutilizepotentialofcompositesthemethodofpredictingdamagefailurefatiguelifewhichshoul

3、dbefittoengineeringisanimptantresearchprojectnowwhichisalsooneofprimaryquestionswhichshouldbeinurgentneedofbeingsolved.Aprogressivedamagemethodofpredictingthestaticstrengththefatiguelifeofmechanicallyfastenedjointsinfibr

4、ereinfcedplasticsisestablishedinthepaperwhichisbasedonthetheyofunidirectionalply.Theequationsofvirtualwkarededucedtoanalyzestressstrainstatesunderstaticfatigueloadingconditions.Nonlinearshearstressstrainbehaviofaunidirec

5、tionalplyinthe1231planesisconsideredintheanalysisofthreedimensionalstressesfthelaminateofmechanicallyfastenedjoints.Theresidualstrengthdegradationmodeltheresidualstiffnessdegradationmodelbasedonthedegradationofstiffnesso

6、fthecompositelaminasubjectedtofatigueloadingsarededucedestablishedbycouplingthenmalizedfatiguelifemethod.ThethreedimensionalHashintypefailurecriteriaareintroducedintothemethodtodetectdamagefdiversedamagemodes.Thecriteria

7、ofthestructurecatastrophethesuddenmaterialpropertydegradationrulesincludingthecrelationamongfourbasicdamagemechanismsarealsoestablished.Asoftwaremoduleofprogressivedamageanalysesfboltedcompositelaminatesiscompiledwhichis

8、convenientftheapplicationinengineering.AnexperimentalprogramwhichincludeslotsofunidirectionallaminaeisconductedusingT300BMP316materialfresearchingthestaticfatiguebehaviouroftheunidirectionalply.Theexperimentalresearchfme

9、chanicalbehaviourofaunidirectionallaminaistosetupexpressionsofthenmalizedfatiguelifetheresidualstrengthdegradationtheresidualstiffnessdegradationofaunidirectionalplyinthelongitudinaltransverseinplanesheardirectionswhicha

10、lsoverifiesthefactofnonlinearshearstressstrainbehaviofaunidirectionalplyinthe12planes.Aseriesofstaticfatigueexperimentswhichincludelotsofspecimensareperfmedonboltedcompositelaminatesthatincludedifferentsizesdifferentlayi