简介：Aclosed-formsolutionforpredictingthetangentialstressofaninclusionlocatedinmixedmodeⅠandⅡcracktipfieldwasdevelopedbasedontheEshelbyequivalentinclusiontheory.Thenamixedmodefracturecriterion,includingthefracturedirectionandthecriticalload,wasestablishedbasedonthemaximumtangentialstressintheinclusionforbrittleinclusioninducedfracturematerials.Theproposedfracturecriterionisafunctionoftheinclusionfracturestress,itssizeandvolumefraction,aswellastheelasticconstantsoftheinclusionandthematrixmaterial.Thepresentcriterionwillreducetotheconventionaloneastheinclusionhavingthesameelasticbehaviorasthematrixmaterial.Theproposedsolutionsareingoodagreementwithdetailedfiniteelementanalysisandmeasurement.

简介：在现在的纸，用MMB(弯曲的混合模式)调查的CFRP的interlaminar破裂坚韧上的碳nanofiber的影响测试。蒸汽成年的碳纤维VGCF和VGCF-S，和多围的碳nanotubeMWNT-7被采用了因为CFRP上的夹层的toughener把压成薄片。以便评估破裂坚韧和它的混合模式比率，两倍弯曲的伸臂横梁(DCB)测试，结束notched破裂(ENF)测试和混合模式(MMB)测试被执行了。边界元素分析被用于CFRP模型计算interlaminar破裂坚韧，在推测方法被用来决定破裂坚韧并且混合了模式比率的地方。interlaminar破裂坚韧和混合模式比率能被压力分发在CFRP的裂缝尖端的附近外推把压成薄片。CFRP的interlaminar破裂坚韧把压成薄片，这被发现被改进插入碳nanofiber特别在砍的区域做的夹层模式变丑是主导的。

简介：Thispaperpresentsanextensionofadisplacementdiscontinuitymethodwithcracktipelements(aboundaryelementmethod)proposedbytheauthorforfatiguecrackgrowthanalysisinplaneelasticmediaundermixed-modeconditions.Theboundaryelementmethodconsistsofthenon-singulardisplacementdiscontinuityelementspresentedbyCrouchandStarfieldandthecrack-tipdisplacementdiscontinuityelementsduetotheauthor.Intheboundaryelementimplementationtheleftorrightcrack-tipelementisplacedlocallyatthecorrespondingleftorrightcracktipontopofthenon-singulardisplacementdiscontinuityelementsthatcovertheentirecracksurfaceandtheotherboundaries.Crackgrowthissimulatedwithanincrementalcrackextensionanalysisbasedonthemaximumcircumferentialstresscriterion.Inthenumericalsimulation,foreachincrementofcrackextension,remeshingofexistingboundariesisnotrequiredbecauseofanintrinsicfeatureofthenumericalapproach.Crackgrowthismodeledbyaddingnewboundaryelementsontheincrementalcrackextensiontothepreviouscrackboundaries.Atthesametime,theelementcharacteristicsofsomerelatedelementsareadjustedaccordingtothemannerinwhichtheboundaryelementmethodisimplemented.Asanexample,thefatiguegrowthprocessofcracksemanatingfromacircularholeinaplaneelasticplateissimulatedusingthenumericalsimulationapproach.

简介：Anewalgorithmforthesolutionofquadraticprogrammingproblemsisputforwardintermsofthemixedenergytheoryandisfurtherusedfortheincrementalsolutionofelastic-plastictrussstructures.Themethodproposedisdifferentfromthetraditionalone,forwhichtheunknownvariablesareselectedjustinoneclasssuchasdisplacementsorstresses.Thepresentmethodselectsthevariablesinthemixedformwithbothdisplacementandstress.Asthemethodisestablishedinthehybridspace,theinformationfoundinthepreviousincrementalstepcanbeusedforthesolutionofthepresentstep,makingthealgorithmhighlyeffi-cientinthenumericalsolutionprocessofquadraticprogrammingproblems.Theresultsobainedintheexam-plesoftheelastie-plasticsolutionofthetrussstructuresverifywhathasbeenpredictedinthetheoreticalanal-ysis.

简介：Inordertoinvestigatethecalculationmethodsoncrackresistancecapacityofconnectioncomposedofcrossshapedsteelencasedultrahighstrengthconcrete(CSSEUHSC)columnsandsteelencasedconcrete(SEC)beamsundercycleloads,sixinteriorconnectionspecimensweretestedinthelaboratory.Adiscussiononthecrackresistancecapacitywaspresented.Calculationmethodsofcrackresistancecapacitywerededucedbasedontheexperimentalcaseandcalculationresultswereingoodagreementwiththeexperimentalresults.TheresearchresultsindicatedthatparametersofconnectioncomposedofCSSEUHSCcolumnsandSECbeamswithbettercrackresistanceperformancemaybereferredforengineeringapplication.

简介：Tosolvethecoupledvibrationofagravitydam-reservoirsystemwithvariablewaterdepthbyusingahybridelementmethod,thefluidregionwithvariablewaterdepthneedstobedis-cretizedbyFEmeshes.However,suchamethodasksforagreatcomputationalcostowingtotheex-cessiveunknowns,especiallywhenthefluidregionwithvariablewaterdepthisrelativelylarge.Toovercometheshortcoming,arefinedboundaryelementmethodisproposedtoanalyzethefluidfield,inwhichonlythediscretizationfortheboundaryofthevariabledepthregionisrequired.Butasabasisofthisapproach,itisnecessarytoconstructanewGreen’sfunctioncorrespondingtoaninfinitestripregion.TheproblemissolvedasthefirststepinthispaperbyemployingFridman’soperatorfunctiontheory,andthenamixedFE-BEformulationforanalyzingthefreevibrationofthegravitydam-reservoirsystemisderivedbymeansofthecouplingconditionsonthedam-reservoirinterface.Final-ly,anumericalexampleisprovidedtoillustrateagreatimprovementofthemethoddevelopedhereinoverthehybridelementmethod.

简介：Softmaterialisbecomingincreasinglyimportanttomanyindustries,whichleadstothedemandforabetterunderstandingofitsmechanicalpropertiesunderlargedeformation.Inthispaper,atechniqueofintegratingthedigitalmoirémethodandembedded-gratingapproachispresentedforinvestigatingmechanicalbehaviorsofavulcanizedsiliconerubberincontactwithawedge-shapedindenter.Twodistinctdeformationsectorsareobservedfromtheexperimentalresult.Asimplewayofcomputingstrainisalsopresentedbyanalysinggriddeformationwithintheframeworkofgeometricalnonlinearity.Threeregionswereobservedfromstraindistributionalongthehorizontaldirection:thecontactregion,thesink-inregionandthefar-fieldregion.Moreover,theextentofthestickyregionandthatoftheslippyregionwithinthecontactinterfacearedistinguished,whichcanproviderealisticdatafortheoreticalmodelling.Basedonthefinitedeformationelasticitytheory,thedistributionofcontactpressureandshearstressoverthecontactinterfacearederivedforpredictionofpossiblecracks.