简介：AmechanicalmodelisestablishedformodeⅡinterfacialcrackstaticgrowingalonganelastic-elasticpowerlawcreepingbimaterialinterface.Forfrictionalcontactofboundaryconditionsoncrackfaces,asymptoticsolutionsofthestressesandstrainsofneartip-crackaregot.Itwasshownthatinstablecreepgrowingphase,elasticdeformationandviscousdeformationareequallydominantinthenear-tipfield,thestressandstrainhavethesamesingularityandthereisnottheoscillatorysingularitythefield.Throughnumericalcalculation,itisshownthatthefrictionalcoefficientηnotablyinfluencethecrack-tipfield.

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简介：Intergranularslowcrackgrowthinzirconiapolycrystalisdescribedwithacohesivezonemodelthatsimulatemechanicallythereaction-rupturemechanismunderlyingstressandenvironmentallyassistedfailure.A2Dpolycrystalisconsideredwithcohesivesurfacesinsertedalongthegrainboundaries.Theanisotropicelasticmodulusandgrain-to-grainmisorientationareaccountedfortogetherwithaninitialstressstaterelatedtotheprocessing.Aminimumloadthresholdisshowntooriginatefromtheonsetofthereaction-rupturemechanismtoproceedwhereaminimumtractionisreachedlocallyandfromthemagnitudeoftheinitialcompressionstresses.Thisworkaimsatprovidingreliablepredictionsinlonglastingapplicationsofceramics.

简介：Formulationintermsofhypersingularintegralequationsfortheinteractionbetweenstraightandcurvedcracksinplaneelasticityisobtainedusingthecomplexvariablefunctionsmethod.Thecurvedlengthcoordinatemethodandasuitablenumericalschemeareusedtosolvesuchintegralsnumericallyfortheunknownfunction,whicharelaterusedtofindthestressintensityfactor,SIF.

简介：Asolutionispresentedforaclassoftwo-dimensionalelectroelasticbranchedcrackproblems.ExplicitGreen’sfunctionforaninterfacecracksubjecttoanedgedislocationisdevelopedusingtheextendedStrohformulationallowingthebranchedcrackproblemtobeexpressedintermsofcoupledsingularintegralequations.Theintegralequationsareobtainedbythemethodthatmodelsakinkasacontinuousdistributionofedgedislocations,andthedislocationdensityfunctionisdefinedonthelineofthebranchcrackonly.Competitionbetweencrackextensionalongtheinterfaceandkinkingintothesubstrateisinvestigatedusingtheintegralequationsandthemaximumenergyreleaseratecriterion.Numericalresultsarepresentedtoshowtheeffectofelectricfieldonthepathofcrackextension.

简介：AnewmechanicsmodelbasedonPeierlsconceptispresentedinthispaper,whichcanclearlycharacterizetheintrinsicfeaturesnearatipofaninterfacialcrack.Thestressanddisplacementfieldsarecalculatedundergeneralcombinedten-sileandshearloadings.Theneartipstressfieldsshowsomeoscillatorybehaviorsbutwithoutanysingularityandthecrackfacesopencompletelywithoutanyoverlappingwhenremotetensileloadingiscomparablewithremoteshearloading.Afracturecriterionforpredictinginterfacetoughnesshasbeenalsoproposed,whichtakesintoaccountfortheshieldingeffectsofemitteddislocations.Thetheoreticaltoughnesscurvegivesexcellentprediction,ascomparedwiththeexistingexperimentdata.

简介：本文从crack技术的初级阶段讲起逐表深入的介绍了一些crack知识或经验。在引出本文之前，我想说的是请大家能正视crack,据我所知的我认识的朋友和了解的cracker,大部分都不是为了金钱而破解的，很多人只是把它当作自己的兴趣而已，所谓的CCG、BCG等破解组织是软件盗版的基地更是无中生有，据我所知每个破解组织的规章其中就严格规定不得和盗版集团发生任何联系。国外也有破解组织而且水平比国内要高，为什么国外的软件能成功？这恐怕不仅仅是crack惹的祸！同时crack同样给我国的共享软件提供了巨大的能量。

简介：这篇论文在有限厚度的一次非同类的材料旅行认为一架反飞机是动人的快克。shear模量和长带的集体密度为平衡方程为有分析答案的功能的形式的一个班被考虑。这个问题借助于单个不可分的方程技术被解决。裂缝尖端附近的压力地被获得。结果被阴谋在裂缝尖端域上显示出材料非同质和快克移动速度的效果。裂缝分叉行为也被讨论。纸指出一个适当破裂标准的使用为在非同类的材料学习一个动人的裂缝的稳定性是必要的。预言不稳定的裂缝生长是否将被提高或延迟，强烈依赖于使用的破裂标准的类型。基于分析，看起来最大值“反飞机砍”在裂缝尖端附近的应力是为在非同类的材料的动人的裂缝的一个合适的失败标准。

简介：Thepresentworkisconcernedwithapenny-shapedDugdalecrackembeddedinaninfinitespaceofone-dimensional(1D)hexagonalquasicrystalsandsubjectedtotwoidenticalaxisymmetrictemperatureloadingsontheupperandlowercracksurfaces.ApplyingDugdalehypothesistothermo-elasticresults,theextentoftheplasticzoneatthecracktipisdetermined.Thenormalstressoutsidetheplasticzoneandcracksurfacedisplacementarederivedintermsofspecialfunctions.Forauniformloadingcase,thecorrespondingresultsarepresentedbysimplifyingtheprecedingresults.Numericalcalculationsarecarriedouttoshowtheinfluenceofsomeparameters.

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简介：Fordecades,nacrehasinspiredresearchersbecauseofitssophisticatedhierarchicalstructureandremarkablemechanicalproperties,especiallyitsextremefracturetoughnesscomparedwiththatofitspredominantconstituent,CaCO3,intheformofaragonite.Crackdeflectionhasbeenextensivelyreportedandregardedastheprincipaltougheningmechanismfornacre.Inthispaper,ourattentionisfocusedoncrackevolutioninnacreunderaquasi-staticstate.Weusethenotchedthree-pointbendingtestofdehydratednacreinsituinascanningelectronmicroscope(SEM)tomonitortheevolutionofdamagemechanismsaheadofthecracktip.Theobservationsshowthatthecrackdeflectionactuallyoccursbyconstrainedmicrocracking.Onthebasisofourfindings,acrackpropagationmodelisproposed,whichwillcontributetouncoveringtheunderlyingmechanismsofnacre’sfracturetoughnessanditsdamageevolution.Theseinvestigationswouldbeofgreatvaluetothedesignandsynthesisofnovelbiomimeticmaterials.

简介：Abriefaccountisprovidedoncrack-tipsolutionsthathaverecentlybeenpublishedintheliteraturebyemployingtheso-calledGRADELAmodelanditsvariants.TheGRADELAmodelisasimplegradientelasticitytheoryinvolvingoneinternallengthinadditiontothetwoLame'constants,inanefforttoeliminateelasticsingularitiesanddiscontinuitiesandtointerpretelasticsizeeffects.Thenon-singularstrainsandnon-singular(butsometimessingularorevenhypersingular)stressesderivedthiswayunderdifferentboundaryconditionsdifferfromeachotherandtheirphysicalmeaninginnotclear.Thisisdiscussedwhichfocusontheformandphysicalmeaningofnon-singularsolutionsforcrack-tipstressesandstrainsthatarepossibletoobtainwithintheGRADELAmodelanditsextensions.

简介：Byusingthemethodofstressfunctions,theproblemofmode-ⅡGriffithcrackindecagonalquasicrystalswassolved.First,thecrackproblemoftwo-dimensionalquasicrystalswasdecomposedintoaplanestrainstateproblemsuperposedonanti-planestateproblemandsecondly,byintroducingstressfunctions,the18basicelasticityequationsoncouplingphonon-phasonfieldofdecagonalquasicrystalswerereducedtoasinglehigherorderpartialdifferentialequations.Thesolutionofthisequationundermixedboundaryconditionsofmode-ⅡGriffithcrackwasobtainedintermsofFouriertransformanddualintegralequationsmethods.Allcomponentsofstressesanddisplacementscanbeexpressedbyelementalfunctionsandthestressintensityfactorandthestrainenergyreleaserateweredetermined.

简介：Thediaphragmofsteamturbineisoneofthemainpartsofthepassageunitforairflowingandthediaphragmofsteamturbineisgenerallymadebywelding,butduringthecourseofwelding,somecracksoftenhavehappened,thesecracksthreatensafetyproductiononthespot,soitisnecessarytoanalyzethestrengthofsteamturbinediaphragmwithacrack.Forstudyingitsworkingconditionandperformancewithacrack,thethree-dimensionalfiniteelementmodel(FEM)withthesoftwareANSYS10.0isestablishedaccordingtotheactualworkingparameters.Withthemodel,thedeformationresultsandstressfieldresultsareanalyzedandthemaximumdisplacementandstressvaluearecalculated,meanwhile,themaximumstresschangewithcrackdepthofsteamturbinediaphragmisanalyzed.Itprovidesagoodfoundationforsolvingtheprobleminproduction.

简介：在同类的压电的脱衣的平行裂缝的一个周期的数组的问题结合了到机能上地分级的压电的材料为不同类的连续统被调查。材料不同类沿着裂缝的方向作为在指数的功能形式的shear模量的空间变化被代表，这被假定。混合边界价值问题被使用Fourier变换归结为一个单个不可分的方程，并且单个不可分的方程被使用Gauss-Chebyshev集成技术数字地解决。数字结果被获得为材料不同类的不同的值作为裂缝频率的一个函数说明压力紧张因素的变化。

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简介：Aconcurrentmultiscalemethodisdevelopedforsimulatingquasi-staticcrackpropagationinwhichthefailureprocessesoccurinonlyasmallportionofthestructure.Forthispurpose,amultiscalemodelisadoptedandbothscalesarediscretizedwithfinite-elementmeshes.Theextendedfiniteelementmethodisemployedtotakeintoaccountthepropagationofdiscontinuitiesonthefine-scalesubregions.Atthesametime,fortheothersubregions,thecoarse-scalemeshisemployedandisresolvedbyusingtheextendedmultiscalefiniteelementmethod.Severalrepresentativenumericalexamplesaregiventoverifythevalidityofthemethod.

简介：Aradialcrackemanatingfromasemi-circularnotchisofsignificantengineeringimportance.Accuratedeterminationofkeyfracturemechanicsparametersisessentialfordamagetolerancedesignandfatiguecrackgrowthlifepredictions.Thepurposeofthispaperistoprovideanefficientandaccurateclosed-formweightfunctionapproachtothecalculationofcracksurfacedisplacementsforaradialcrackemanatingfromasemi-circularnotchinasemi-infiniteplate.Resultsarepresentedfortwoloadconditions:remoteappliedstressanduniformstresssegmentappliedtocracksurfaces.Basedonacorrectionofstressintensityfactorratio,highlyaccurateanalyticalequationsofcracksurfacedisplacementsunderthetwoloadconditionsaredevelopedbyfittingthedataobtainedwiththeweightfunctionmethod.ItisdemonstratedthattheWuCarlssonclosed-formweightfunctionsareveryefficient,accurateandeasy-to-useforcalculatingcracksurfacedisplacementsforarbitraryloadconditions.Themethodwillfacilitatefatiguecrackclosureandotherfracturemechanicsanalyseswhereaccuratecracksurfacedisplacementsarerequired.

简介：Experimentalrevelationofsuperbluntingalongplanestrainpredominantcracktipsegmentisre-portedhereformodifiedpolyproplene.Aselucidatedbyaheuristicmodelofprogressivecircumferentialcold-draw,theformationofsuperbluntingcracktipdependscriticallyontheratiobetweenthecold-drawprop-agationspeedandtheloadingspeed,andcontributessignificantlytothematerialtoughening,especiallyfortheimprovementinimpacttoughness.Detailednumericalcalculationsareconductedbasedonahyperelastic-viscoplasticandanisotropicdamageconstitutivemodelatfinitedeformation.Thesimulatedresultsrecapitulatetheessentialfeaturesofcracktipsuperblunting.