简介：Inthispaper,anonlocaltheoryoffractureforbrittlematerialshasbeensystematicallydevel-oped,whichiscomposedofthenonlocalelasticstressfieldsofGriffithcracksofmode-Ⅰ,ⅡandⅢ,theasymptoticformsofthestressfieldsattheneighborhoodofthecracktips,andthemaximumtensilestresscriterionforbrittlefracture.Asanapplicationofthetheory,thefracturecriteriaofcracksofmode-Ⅰ,Ⅱ,ⅢandmixedmodeⅠ-Ⅱ,Ⅰ-Ⅲaregivenindetailandcomparedwithsomeexperimentaldataandthetheoreticalresultsofminimumstrainenergydensityfactor.

简介：Thisinvestigationdiscussesfurthertheextenttowhichanewdamagetheoryrecentlyproposedbytheauthorcanserveasaunifiedtheorytocharacter-izevariousductilefailureproblems.Ageneraldamageintegralandcorrespondingcriterionforductilefracturearepresented.Anewparameterforductilefractureisemphasized,whichisexperimentallyverifiedasamaterialconstantindependentofstressstate,hasclearphysicalmeaning,andcaneasilybedetermined.Theapplica-bilityofthistheorytoevaluationoftheductilityofweldsandengineeringmaterialsundervariousconditionsisexamined.Also,itisusedtopredicttheeffectofresid-ualstressonfailureofwelds,topredictsheetforminglimits,andtocorrelatethevariabilityofelasto-plasticfracturetoughnessvaluesJ1candδcwithdifferentspec-imengeometries.Anewconstraintcorrectionmethodisproposed,andconstraintcorrectednewtoughnessparametersJdcandδdcarerecommended.Experimentshaveshownthatthetoughnessvariationwithdifferentspecimengeometriescanef-fectivelyberemovedbyuseofthemethod.Thegeneralapplicabilityofthetheorytocharacterizationofvariousductilefailuresprovidesanewdesigntoolforengineeringcomponentsorstructures.

简介：在一台半导体设备构造一根相连的金属线的原子被电子流动在高密度搬运。这现象被称为electromigration，它可以引起线失败。以便描绘electromigration失败，比较研究被执行，一些典型现象为薄、大的结构由破裂力学对待。薄结构的一个例子，被破裂力学对待，是硅石为通讯系统的光纤维。在由electromigration的一根金属线的损坏生长在光纤维使遭到了到静态的疲劳的硅石与裂缝生长比较被描绘。另外，简短比较在大结构在electromigration失败和一些破裂现象之间被做。

简介：Inphasefieldfracturemodelsthevalueoftheorderparameterdistinguishesbetweenbrokenandundamagedmaterial.Atcrackfacestheorderparameterinterpolatessmoothlybetweenthesetwostatesofthematerial,whichcanberegardedasphases.Thecrackevolutionfollowsimplicitlyfromthetimeintegrationofanevolutionequationoftheorderparameter,whichiscoupledtothemechanicalfieldequations.Amongotherphenomenaphasefieldfracturemodelsareabletoreproducecracknucleationininitiallysoundmaterials.Fora1Dsettingithasbeenshownthatcracknucleationistriggeredbythelossofstabilityoftheunfractured,spatiallyhomogeneoussolution,andthatthestabilitypointdependsonthesizeoftheconsideredstructure.Thisworknumericallyinvestigatestowhichextendsizeeffectsarereproducedbythe2Dphasefieldmodel.Exemplarily,afiniteelementstudyoftheholesizeeffectisperformedandthesimulationresultsarecomparedtoexperimentaldata.

简介：Theacousticemission(AE)featuresinrockfracturearesimulatednumericallywithdiscreteelementmodel(DEM).Thespecimenisconstructedbyusingsphericalparticlesbondedviatheparallelbondmodel.Asaresultoftheheterogeneityinrockspecimen,thefailurecriterionofbondedparticleiscoupledbytheshearandtensilestrengths,whichfollowanormalprobabilitydistribution.TheKaisereffectissimulatedinthefractureprocess,foracubicrockspecimenunderuniaxialcompressionwithaconstantrate.TheAEnumberisestimatedwithbreakagesofbondedparticlesusingapairofparameters,inthetemporalandspatialscale,respectively.ItisfoundthattheAEnumbersandtheelasticenergyreleasecurvescoincide.TherangefortheKaisereffectfromtheAEnumberandtheelasticenergyreleasearethesame.Furthermore,thefrequency-magnituderelationoftheAEnumbershowsthatthevalueofBdeterminedwithDEMisconsistentwiththeexperimentaldata.

简介：一个基于Hamiltonian的分析方法被用来与一个有瑕疵的接口在magnetoelectroelasticbimaterials学习模式III接口裂缝。由介绍未知向量，管理方程是在一阶的平常的微分方程的集合的reformulated。用变量的分离，在symplectic空格的eigensolutions被获得。未知向量的一个准确答案以symplectic被获得并且表示eigensolutions。奇特机械，电，并且磁场与概括紧张因素被评估。比较被做验证建议方法的精确性和稳定性。包括混合边界条件的数字例子被给。

简介：Bymeansofreasonableassumptionandmathematicalderivation,atheoreticexpressionofflowrateforasinglefracturewithlinearlyvaryingwidthwasobtained.Themathematicalderivationwasbasedonthecubiclawandthenewtheoreticexpressionwasanextentionoftraditionalparallelplatemodel.Thisstudymayhelptoanalyzeseepageinfracturedrockmass.

简介：Thisstudyconcernsatwo-dimensionalmodelandthecorrespondingvirtualcrackclosuretechnique(VCCT)implementedtosolvethegeneralboundaryvalueproblemsthatmayexplainwhyinterfacediscontinuityhaseffectsonthefracturebehaviorinthesuperconductor-substratesystem.Theinterfacialdiscontinuitycanbeclassifiedaccordingtothematerialproperties'continuityandtheirderivatives'continuityattheinterface.Fornonhomogeneoussuperconductorandsubstratespecimenswithvariousmaterialproperties,aVCCTmethodisdevelopedtocalculatetheirfracturebehavior.Furthermore,theeffectsofappliedmagneticfieldamplitudeandnonhomogeneousparametersareextensivelyandparametricallystudiedintwoactivationprocesses(zero-fieldcoolingandfieldcooling).Theintegrativeandcomputationalstudypresentedhereprovideafundamentalmechanisticunderstandingofthefracturemechanisminthesuperconductor-substratesystemandshedslightontherationaldesignofinterfacialcontinuity.

简介：Jep积分为描绘有弹性塑料的材料的破裂行为被导出。Jep积分不同于米饭J积分因为工作的免费精力密度而非压力密度被采用定义精力动量张肌。Jep积分被证明不管增长粘性和变丑粘性是路径依赖者。Jep积分拥有清楚地清楚的物理意思：(1)在包围裂缝尖端的无穷地小的轮廓上评估的价值Jtipep代表裂缝尖端精力驱散；(2)当全球steadystate裂缝生长条件被接近时，沿着边界轮廓计算的Jfar-ssep的价值等于到裂缝尖端驱散和塑料地区的体积驱散的和。理论结果被模仿我击碎的模式验证问题。

简介：Aunifieddamageandfracturemodel,thecombinatoryworkdensitymodel,whichissuitableforei-thernon-crackedbodyorcrackedbodyhasbeensuggested.Inthepresentpaper,thedeformationandfractureofthetwokindsoftensilespceimenandTPBspecimenmadeof40Crsteelhavebeensimulatedbyusingthenewmod-eltogetherwiththelargeèlastic-plasticdeformationfiniteelementmethod.Theresultsgiveagoodpictureofthewholedeformationandfractureprocessesofthespecimensinexperiments;especially,theresultsontheTPBspecimencanbeusedtoobtaintherelationshipbetweenloadanddisplacementattheloadingpointP-Δ,andbetweencrackex-tensionanddisplacementattheloadingpointΔα-Δ,theresistancecurveJR-ΔaandthefracturetoughnessJIC.Alltheresultsareinremarkableagreementwiththoseobtainedbyexperiments.Thereforethemodelsuggestedherecanbeusedtosimulatecrackinitiationandpropagationinnon-crackedbodyandfractureinitiationandcrackstablepropa-gationincrackedbody.

简介：这研究试图调查trabecular的地区性的变化，以及决定在trabecular之间的关系词法参数和大腿骨的头的机械参数词法、机械的参数。从有折断的近似腿节的病人的七个大腿骨的头用一个micro-CT系统被扫描。每个大腿骨的头根据trabecular取向被划分成12个分区。一\(125\，\hbox{公里}^{3}\)trabecular立方的模型从每个分区被重建。81个trabecular模型的一个总数被重建，除了从在外科期间的二个大腿骨的头的三个破坏分区。Trabecular词法参数，即trabecular分离(Tb.Sp)，trabecular厚度(Tb.Th)，特定的骨头表面(BS/BV)，骨头体积部分(BV/TV)，结构的模型索引(SMI)，和anisotropy(DA)的度被测量。微有限的元素分析被执行让每个立方体获得明显的幼仔模量，织物水平von协定在1%下面强调分发沿着三个直角的方向的压缩紧张分别地。结果在词法参数揭示了重要地区性的变化(\(P)。沿着trabecular取向的幼仔moduli比沿着另外的二个方向的那些显著地高。一般来说，trabecular在中间的区域的机械性质是比在侧面的区域的那些低的。沿着trabecular取向的Trabecular机械参数显著地与BS/BV，BV/TV，Tb.Th，和DA被相关。在这研究，在有近似腿节骨折的病人的大腿骨的头的微结构特征和机械性质的地区性的变化彻底地在组织水平被调查。这研究的结果将帮助阐明为减少破裂风险和发展中的治疗策略为的大腿骨的头骨折的机制老。

简介：

简介：Thetransientfracturebehaviorofafunctionallygradedlayeredstructuresubjectedtoanin-planeimpactloadisinvestigated.Thestudiedstructureiscomposedoftwohomogeneouslayersandafunctionallygradedinterlayerwithacrackperpendiculartotheboundaries.Theimpactloadisappliedonthefaceofthecrack.FouriertransformandLaplacetransformmethodsareusedtoformulatethepresentproblemintermsofasingularintegralequationinLaplacetransformdomain.Consideringvariationsofparameterssuchasthenonhomogeneityconstant,thethicknessratioandthecracklength,thedynamicstressintensityfactors(DSIFs)intimedomainarestudiedandsomemeaningfulconclusionsareobtained.

简介：Onthebasisofplasticityandfracturemechanicsforquasi-brittlematerials,thisarticlepresentedaconstitutivemodelforgradualsofteningbehaviorofjointsofgeomaterials.Correspondingnumericaltestsarecarriedoutatthelocallevel.Characteristicsofthemodelproposedare1)plasticsofteninganddilatancybehavioraredirectlyrelatedtothefractureprocessofjoint,andmuchlessmaterialandmodelparametersarerequiredcomparedwiththoseproposedbyreferences;2)theprocessofdecohesioncoupledwithfrictionalslidingatbothmicro-scaleandmacro-scaleisdescribed.

简介：部分地，聪明切割的过程，缺陷由尺寸描绘了的结合的效果和在切开前后的内部压力上的2纸被使用破裂力学模型学习。有大尺寸的结合的缺陷是容易的引起缺点生长的严重偏差，这被发现，当切开时，导致薄层的一个非转移的区域。在结合的缺陷的内部压力是很小的一个实际聪明切割的过程，大界面的缺点总是在切开的过程支持缺点生长。同时，增加结合的缺陷的内部压力减少在切开前的缺点生长和它的偏差。stiffener限制的松驰的机制被建议澄清结合的缺陷的效果。而且，当结合的缺陷是在场的时，切开的过程的进步被分析。在切开以后，有大尺寸和高内部的压力的那些结合的缺陷在高温度的退火期间为薄电影的blistering是脆弱的。

简介：Polymerbondedexplosives(PBXs)arehighlyparticle-filledcompositematerials.ThispaperexperimentallystudiesthetensiledeformationandfracturebehaviorofaPBXsimulationbyusingthesemi-circularbending(SCB)test.Thedeformationandfractureprocessofapre-notchedSCBsamplewitharandomspecklepatternisrecordedbyachargecoupleddevicecamera.Thedisplacementandstrainfieldsontheobservedsurfaceduringtheloadingprocessareobtainedbyusingthedigitalimagecorrelationmethod....