vcct(虚拟裂纹扩展分析技术).doc

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1、.Vcct(Virtualcrackclosuretechnique)Interlaminarfracturemechanicscharacterizestheonsetofdelaminationsincomposites.Shearloadingcausesthepaneltobuckleandtheresultingout-of-planedeformationsinitiateskin/stringerseparat

2、ionatthelocationofanembeddeddefect.METHOD:FiniteElementAnalysisELEMENT:thepanelandsurroundingloadfixtureweremodeledwithshellelements.Asmallsectionofthestringerfootandthepanelinthevicinityoftheembeddeddefectweremodeledwithalocal3Dsoilmodel.1.BACKGROUNDAerospacesstructuresaremadeoffl

3、atorcuredpanelswithco-curedoradhesivelybondedframesandstiffenerscomputationalstressanalysistodeterminethelocationoffirstmatrixcracking.Anartificialdefectwasplacedattheterminationofthecenterstiffener.Thestiffenedpanelissubjectedtopureshearloadingwhichcausesthepaneltobuckle.ANALYSIS:

4、nolinearfiniteelementanalysisStrainenergyreleaseratesandmixedmaderatioswerecomputedusingthevirtualcrackclosuretechnique.2.METHODOLOGY2.1InterlaminarfracturemechanicsThetotalstrainenergyreleaserateThemodeIcomponentduetointerlaminartensionThemodeIIcomponentduetointerlaminarslidingshe

5、arThemodeIIIcomponentduetointerlaminarscissoringshearWord文档资料.Purpose:topredictdelaminationonsetorgrowthfortwo-dimensionalproblems,thesescalculatedGcomponentsarecomparedtointerlaminarfracturetoughnesspropertiesmeasuredoverarangeofmodemixitiesfrompuremodeIloadingtopuremodeIIloading.

6、Aquasistaticmixed-modefracturecriterionisdeterminedbyplottingtheinterlaminarfracturetoughness,,versusthemixed-moderatio,,determinedfromdatageneratedusingpureModeI()DoubleCantileverBending(DCB)pureModeII()fourpointEndNotchedFlexure(4ENF),andMixedModeBending(MMB)testsofvaryingratiofo

7、rIM7/8852carbonepoxymaterial.andarethefracturetoughnessdataformodeIandIIisafactordeterminedbythecurefit.Showninfigure3inthisarticle.Failureisexpectedwhen,foragivenmixedmoderatioWord文档资料.,thecalculatedtotalenergyreleaserate,,exceedstheinterlaminarfracturetoughness,.1.1.AnalysisTools

8、2.2.1.VirtualCrackClosureT