简介：ThereisuptonownoconstitutivemodelinthecurrenttheoriesofCDMthatcouldgiveadescriptionforthedegradationofagingconcrete.Thetwointernalstatevariablesβandωareintroducedinthispaper.βiscalledcohesionvariableasanadditionalkinematicparameter,reflectingthecohesionstateamongmaterialparticles.ωiscalleddamagefactorformicro-defectssuchasvoids.ThenadamagemodelandaseriesofconstitutiveequationsaredevelopedonContinuumMechanics.Themodelproposedcouldgiveavaliddescriptionforthewhole-course-degradationofagingconcreteduetochemicalandmechanicalactions.Finally,thevalidityofthemodelisevaluatedbyanexampleandexperimentalresults.

简介：Domainswitchingisthemainsourceofnonlinearcharacteristicsinferroelectrics.Accordingtocrystalplasticitytheory,thedomainsanddomainswitchingsystemsforperovskitetypestructureferroelectricsaredefined.Consideringthetraversemotionperformanceofdomainwall,arathersimplifiedformofevolutionlawaboutincrementalofvolumefractionduringdomainswitchinghasbeendeveloped.Themainfactors,whichexertaninfluenceondomainswitching,suchasmaterialparameters,domainwallmotionhistory,kindofdomainswitching(180°or90°)andvolumefraction,couldbeaddressed.Thehysteresisloopsofspontaneouselectricpolarizationasafunctionofelectricfield,thebutterflyshapedstrainversuselectricfieldcurveandtheplatformrelationsbetweenspontaneouspolarizationandstress,aswellasthelongitudinalstrainandstress,arewellsimulatedanddiscussed.

简介：一个适应neuro模糊的推理系统(ANFIS)被介绍预言横梁的动态行为。轴的力量和大排水量的效果在分析被考虑。为横梁的动态特征的测试的一个数据库从试验性的测试被开发。为单个、多重步的横梁的非线性的颤动力量的回答从有限元素方法被计算(女性)，为比较的试验性的测试和neuro模糊的模型。neuro模糊的模型为神经网络和模糊逻辑的联合提供一个一般框架。它与合并真实世界的系统的模糊性质的更多的选择是更灵活的并且是为横梁的动态特征的一个有用评价工具。因此，ANFIS能是为受到轴的负担和大排水量的多重步的横梁的动态行为分析的一个有用工具。

简介：Anin-depthinvestigationismadeontheproblemofanarc-shapedinterfaceinsulatingcrackinathree-phaseconcentriccircularcylindricalpiezoelectriccompositeconstitutivemodel.Anexactsolutioninseriesformisderivedbyemployingthecomplexvariablemethod.Inaddition,thedistributionofphysicalquantitiessuchasstresses,strains,electricdisplacementsandelectricfieldsinthewholefieldandalongtheinterfaceisalsopresented.Explicitexpressionsforcrackopeningdisplacement,jumpinelectropotentialonthecracksurfaceandtheelectro-elasticfieldintensityfactorsatthecracktipsareobtained.Specificcalculationsdemonstratethattheconvergenceoftheseriesformsolutionissatisfactoryandthattheouterphase(compositephase)willexertasignificanteffectontheelectro-mechanicalcouplingresponseofthecompositesystem.Owingtothefactthatstressesandelectricdisplacementsstillpossessconventionalinversesquarerootsingularities,theoscillatingsingularitiesnearthecracktipunderplanestrainconditionswillbeabsentand,asaresult,nounphysicalinterpenetrationphenomenonofthetwocracksurfaceswilloccur.Inconclusion,theelasticsolutionobtainedisalsobasedonasolidphysicalfoundation.

简介：在硫酸盐离子的攻击下面的水泥臼的扩大性质被试验性、理论的方法学习。首先，水泥臼与水的比率被制作到0.4，0.6，和0.8的水泥。第二，标本的扩大在硫酸盐答案埋头了在不同时间被测量。第三，在硫酸盐侵蚀下面的水泥臼的扩大的一个理论模型被优点建议代表体积元素方法。在这个模型，损坏进化由于在推迟的ettringite和水泥臼之间的相互作用被考虑。最后，数字计算被执行。数字、试验性的结果显示模型完美地描述水泥臼的扩大。

简介：Aprecisetangentialcontactdampingmodelisproposed,whichincludesthelateralcontactoftheupper-lowerasperitiesandtheinteractionofadjacentasperities.Theeffectsofthenormalstaticpreload,frequency,andamplitudeoftangentialdisplacementonthetangentialcontactdampingwereanalyzedbysimulation,respectively.Furthermore,theresultsofsimulationareverifiedbyexperiment.Thetangentialcontactdampingofconsideringtheinteractionandlateralcontactofasperityisveryclosetotheexperimentalresults.

简介：Dynamicstrainaging（DSA）isanimportantphenomenoninsolutehardenedmetalsandseri-ouslyaffectsthemechanicalpropertiesofmetals.DSAisgenerallyinducedbytheinteractionbetweenthemovingdislocationsandthemobilesoluteatoms.Inthispaper,onlytheinteractionbetweenmovingdisloca-tionsandmobilesoluteatomsinadislocationcorearea（coreatmosphere）willbetakenintoaccount.Toes-rablishtheconstitutivemodelwhichcandescribetheDSAphenomenon,weimprovedtheZerilli-Armstrongdislocation-mechanics-basedthermalviscoplasticconstitutiverelation,andaddedtheeffectoftheinteractionbetweenthemovingdislocationsandcoreatmosphere.BecausetheconstitutiverelationestabhshedisbasedontheZerilh-Armstrongrelation,itcandescribenotonlytheDSAphenomenon,butalsothemechanicalbe-haviorofmetalsoverabroadrangeoftemperatures（77K～1000K）andstrainrate(10-4～104s-1).Themodelpredictionfortantalumfitswellwiththeexperimentaldata.

简介：仅仅二个宏观的参数被需要描述线性有弹性的固体的机械性质，即泊松的比率和幼仔是模量。相应地，应该有二个显微镜的参数如果线性有弹性的固体的宏观的机械性质从显微镜的水平被导出，决定材料的机械性质。由这个想法照亮了，为材料的一个多尺度的机械模型，虚拟multi-dimensionalinternal契约(VMIB)模型，被把一张shear契约合并到虚拟内部契约(VIB)建议模型。由这修正，VMIB模型联系宏有分离结构和相应关系在之间的显微镜的机械性质的材料的机械性质微并且宏参数被导出。精力密度功能的张肌质量，包含并列向量，算术地被证明。从观点ofVMIB，材料的宏观的非线性的行为能被归因于强加的变丑导致的虚拟契约分发密度的进化。与这个理论假设，作为一个申请例子，易碎的材料的单轴的压缩失败被模仿。在试验性的结果和模仿的之间的好同意被发现。

简介：一个简单立方的格子的脱臼方程被与微分术语和不可分的术语预先明确地被给了的秒顺序的系数基于分离格子理论使用格林的功能方法获得了。我们讨论了的简单立方的格子是一个可解决的模型，它根据格子静电干扰和对称原则被获得并且能验证并且验证脱臼格子理论。它能介绍对大多数有仲裁格子结构的金属合适的统一脱臼方程。通过把现在的可解决的模型的结果与脱臼格子理论作比较，这能被看见，然而，我们获得的边和螺丝钉部件的不可分的术语的系数根据脱臼格子理论的结果螺丝钉部件的微分术语不与脱臼格子理论的结果一致的秒顺序的系数。这被表面术语的减少的动态矩阵主要引起，它是本质获得脱臼方程。根据简单立方的可解决的模型，不是仅仅直脱臼而且弄弯的脱臼的意见，例如纽结，能进一步被调查。

简介：一个组成的模型为转变，重取向和形状记忆合金(SMA)的塑料变丑被开发。它基于SMA是由奥氏体和马氏体组成的混合物的概念，每个阶段的体积部分与使用的热机械的装载的变化是可变形的，并且SMA的组成的行为是它的二个阶段的单个行为的联合。马氏体的变丑被分开成橡皮，热，重取向和塑料部分，和奥氏体的被分开成有弹性、热、塑料的部分。使用田中的转变规则由考虑塑料变丑的效果修改了，SMA的组成的模型被获得。ferroelasticity，SMAAu-47.5at.%Cd的pseudoelasticity和形状记忆效果，和pseudoelasticity和形状记忆象塑料一样完成变丑和它NiTiSMA的效果，被分析并且与试验性的结果相比。

简介：Anenergy-dissipationbasedviscoplasticconsistencymodelispresentedtodescribetheperformanceofconcreteunderdynamicloading.Thedevelopmentofplasticityisstartedwiththethermodynamichypothesesinorderthatthemodelmayhaveasoundtheoreticalbackground.Independenthardeningandsofteningandtheratedependenceofconcretearedescribedseparatelyfortensionandcompression.AmodifiedimplicitbackwardEulerintegrationschemeisadoptedforthenumericalcomputation.Staticanddynamicbehaviorofthematerialisillustratedwithcertainnumericalexamplesatmaterialpointlevelandstructurallevel,andcomparedwithexistingexperimentaldata.Resultsvalidatetheeffectivenessofthemodel.

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简介：在张力的联合的远地下面与一个嵌入的椭圆形的裂缝在一个无限的各向同性的有弹性的矩阵基于变丑的分析并且砍压力，精力版本率和一个混合破裂标准用一条精力平衡途径被获得。单个开的椭圆形的microcrack在一个代表性的体积元素导致的另外的依从张肌被导出，并且有随机的取向的microcracks的效果被介绍适当概率密度功能与泰勒的计划分析。为岩石和水泥的一个micromechanical损坏模型与试验性的结果被获得并且被验证。

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简介：Theboundaryelementmethodisusedforthemodalanalysisoffreevibrationof2-Dcompositestructuresinthispaper.Sincetheparticularsolutionmethodisusedtotreatthetermsofbodyforces(inertialforces)intheequationofmotion,onlystaticfundamentalsolutionsareneededinsolvingtheproblem.Foranisotropiccantileverbeam,thenumericalresultsobtainedbyusingtheBEMpresentedinthispaperareingoodagreement,withthoseofusingFEMorotherBEM,butthisBEMcanalsobeusedtoanalyzeproblemsforanisotropicmaterials.Forsimplysupportedcompositelaminatedbeams,thecomparisonsofthenumericalresultsobtainedbythismethodwiththeanalyticalresultsobtainedby1-Dlaminatedbeamtheoryindicatethatiftheratiooflength/thicknessisgreaterthan20,theresultsofthetwomethodsareingoodagreement,butiftheratiooflength/thicknessislessthan20,bigerrorswilloccurfor1-Dlaminatedbeamtheory.

简介：Amolecularnetworkconstitutivemodelisproposedinthisstudy.Basedontheconceptofmolecularnetworkdecomposition,themolecularnetworkwasdecomposedintoaJames-Guth3-chainnetworkmodelandanArruda-Boyce8-chainnetworkmodel.Consideringthatthesinglemolecularchainofrubberisconstrainedbythesurroundingmolecularnetworks,the3-chainmodelandthe8-chainmodelwereconsequentlymodifiedusingthetubetheory.Theproposedmodelcontainsfourmaterialparametersthatweredeterminedbyfittingtheuniaxialtensiletestdatafromrubber-likematerials,andthevaluesoftheseparameterswereutilizedtodeterminethepureshearandthebiaxialextension.Theproposedmodelagreeswellwiththeexperimentaldataandcanpredictthetestresultsofexperimentsperformedundertheconditionsofpureshearandequi-biaxialdeformationwithacceptableaccuracy.

简介：Anon-localcontinuummodelforstrain-softeningsimplytakingplasticstrainordamagevari-ableasanon-localvariableisderivedbyusingtheadditivedecompositionprincipleoffinitedeformationgra-dient.Atthesametime,variationalequations,theirfiniteelementformulationsandnumericalconvolutedintegrationalgorithmofthemodelincurrentconfigurationusuallycalledco-movingcoordinatesystemaregiven.Stabilityandconvergenceofthemodelareprovenbymeansoftheweakconvergencetheoremofgen-eralfunctionandtheconvolutedintegrationtheory.Mathematicalandphysicalpropertiesofthecharacteris-ticsizeformaterialorstructureareaccountedforwithinthecontextofastatisticalweightedorkernelfunc-tion,andwayisinvestigated.Numericalsimulationshowsthatthismodelissuitablefortoanalyzingdefor-mationlocalizationproblems.

简介：Animprovedmodelforultrasonictransducersisproposed.Byconsideringonlythefirstsymmetricmode,eachlayerisrepresentedasanacousticaltransmissionlineinmodelingofbulkwavetransducers.Inimagingapplications,widebandwidthandshorttimedurationarerequired.Theapproachwehaveusedconsistsofimpedancematchingthefrontfaceofthepiezoelectrictransducertothepropagatingmediumwithaquarterwavelengthimpedancematchinglayerandinsertinganunmatchingquarterwavelengthacousticallayerbetweentherearfaceandbackingmaterial.Aheavybackingwoulddegradethewide-bandphenomena,butshowatimedurationshorterthan0.5μsforimagingapplications.PSPICEcodeofthecontrolledsourcemodelisimplementedtopreciselypredicttheperformanceofthematchedtransducerssuchasimpedance,insertionloss,bandwidthanddurationoftheimpulseresponse.Goodagreementbetweenthesimulationandexperimentalresultshasbeenachieved.

简介：纤维增强的聚合物(FRP)composites逐渐地正在被用于修理并且通过粘合剂预制长带/板和织物的湿上篮结合败坏的具体结构的部件加强。因为重要性，界面的契约失败模式吸引了研究人员的注意。现在的学习的目的是分析连续横梁由FRP加强了的增强的水泥的接口失败机制。一个分析答案第一被介绍了预言模型的全部debonding过程。现实主义的双线性的契约滑倒界面的法律被采用学习这个问题。装载模型的裂缝繁殖过程被划分成四个阶段(橡皮，有弹性弄软，elastic-softening-debonded和softening-debonded舞台)。在他们之中，elastic-softening-debonded舞台有四亚阶段。方程被增加合适的压力和排水量边界条件解决。最后，契约长度的批评价值决心在由解决同时线性的代数学的方程有效的纸做失败机制。如果concrete-to-plate棱柱的轴的僵硬比率足够大，在上面、更低的FRP盘子之间的相互作用能被忽视。

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