简介：Whethertheconceptofeffectivestressandstraininelastic-plastictheoryisstillvalidundertheconditionoffinitedeformationwasmainlydiscussed.Theuni-axialcompressionexperimentsinplanestressandplanestrainstateswerechosenforstudy.Inthetwokindsofstressstates,thestress-straincurvedescribedbylogarithmstrainandrotatedKirchhoffstressmatchestheexperimentsdatabetterthanthecurvesdefinedbyotherstressstraindescription.

简介：Optimizationofcompositionandmicrostructureisimportanttoenhanceperformanceofsolidoxidefuelcells(SOFC)andlithium-ionbatteries(LIB).Forthis,theporouselectrodestructuresofbothSOFCandLIBaremodeledasabinarymixtureofelectronicandionicconductingparticlestoestimateefectivetransportproperties.Particlepackingsof10000spherical,binarysizedandrandomlypositionedparticlesarecreatednumericallyanddensifiedconsideringthediferentmanufacturingprocessesinSOFCandLIB:thesinteringofSOFCelectrodesisapproximatedgeometrically,whereasthecalenderingprocessandvolumechangeduetointercalationinLIBaremodeledphysicallybyadiscreteelementapproach.Acombinationofatrackingalgorithmandaresistornetworkapproachisdevelopedtopredicttheconnectivityandefectiveconductivityforthevariousdensifiedstructures.ForSOFC,asystematicstudyoftheinfluenceofmorphologyonconnectivityandconductivityisperformedonalargenumberofassemblieswithdiferentcompositionsandparticlesizeratiosbetween1and10.Incomparisontopercolationtheory,anenlargedpercolationareaisfound,especiallyforlargesizeratios.Itisshownthatincontrasttoformerstudiesthepercolationthresholdcorrelatestovaryingcoordinationnumbers.Theefectiveconductivityshowsnotonlyanincreasewithvolumefractionasexpectedbutalsowithsizeratio.ForLIB,ageneralincreaseofconductivityduringtheintercalationprocesswasobservedincorrelationwithincreasingcontactforces.Thepositiveinfluenceofcalenderingonthepercolationthresholdandtheefectiveconductivityofcarbonblackisshown.Theanisotropycausedbythecalenderingprocessdoesnotinfluencethecarbonblackphase.

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简介：Severaleffectivenumericalmethodsforsolvingtheelasto-plasticcontactproblemswithfrictionarepres-ented.First,adirectsubstitutionmethodisemployedtoimposethecontactconstraintconditionsoncondensedfiniteele-mentequations,thusresultinginareductionbyhalfinthedimensionoffinalgoverningequations.Second,analgorithmcomposedofcontactconditionprobesandelasto-plasticiterationsisutilizedtosolvethegoverningequation,whichdistinguishestwokindsofnonlinearities,andmakesthesolutionunique.Inaddition,Positive-NegativeSequenceModifica-tionMethodisusedtocondensethefiniteelementequationsofeachsubstructureandananalyticalintegrationisintro-ducedtodeterminetheelasto-plasticstatusaftereachtimesteporeachiteration,hencethecomputationalefficiencyisen-hancedtoagreatextent.Finally,severaltestandpracticalexamplesarepressentedshowingthevalidityandversatilityofthesemethodsandalgorithms.

简介：Thermaltransportinahighlyporousmetallicwire-wovenbulkKagome(WBK)isnumericallyandanalyticallymodeled.Basedontopologysimilarityanduponintroducinganelongationparameterinthermaltortuosity,anidealizedKagomewithnon-twistedstrutsisemployed.SpecialfocusisplaceduponquantifyingtheeffectoftopologicalanisotropyofWBKuponitseffectiveconductivityItisdemonstratedthattheeffectiveconductivityreduceslinearlyastheporosityincreases,andtheextentofthereductionissignificantlydependentontheorientationofWBK.ThegoverningphysicalmechanismofanisotropicthermatransportinWBKisfoundtobetheanisotropicthermaltortuositycausedbytheintrinsicanisotropictopologyofWBK.

简介：模仿实验室元素测试的分离元素方法(DEM)模型在推进我们小粒的材料反应的力学的理解起一个重要作用，包括结合或cemented，微粒材料。在真实物理测试和一个虚拟模仿DEM的测试罐头观察的宏规模反应的比较校准或验证DEM模型。详细说明，在DEM模拟提供的粒子规模信息然后能被用来开发我们材料行为的理解。精确地在这些DEM模拟为物理测试边界条件建模是重要的。这份报纸明确地认为这些测试通常在土壤被使用的triaxial测试是力学。在triaxial测试，小粒的材料的测试标本在允许材料在测试期间自由地使变形的灵活乳胶膜以内被围住，当维持一个指定压力条件时。Triaxial测试能写实地仅仅在3DDEM代码被模仿，然而类似物，2D，因为在二种尺寸设想粒子相互作用更容易，biaxialDEM模拟经常也被考虑。这份报纸描述算法模仿在2D和3DDEM模拟的物理triaxial测试使用的乳胶膜强加的侧面的边界条件。小心地在DEM模拟考虑侧面的边界条件的重要性被在摩擦unbonded磁盘和3Dtriaxial测试的一个标本上考虑2Dbiaxial测试在上说明一结合(cemented)范围的标本。比较显示侧面的边界条件在本地人，上有更重要的影响与全面宏规模观察比较的粒子规模反应。

简介：Acomparativeoptimaldesignoffluid-saturatedprismaticcellularmetalhoneycombs(PCMHs)havingdifferentcellshapesispresentedforthermalmanagementapplications.BasedontheperiodictopologyofeachPCMH,aunitcell(UC)forthermaltransportanalysiswasselectedtocalculateitseffectivethermalconductivity.Withoutintroducinganyempiricalcoefficient,wemodifiedandextendedtheanalyticalmodelofparallel–seriesthermal–electricnetworktoawiderporosityrange(0.7~0.98)byconsideringtheeffectsoftwo-dimensionallocalheatconductioninsolidligamentsinsideeachUC.Goodagreementwasachievedbetweenanalyticalpredictionsandnumericalsimulationsbasedonthemethodoffinitevolume.Theconceptofligamentheatconductionefficiency(LTCE)wasproposedtophysicallyexplainthemechanismsunderlyingtheeffectsofligamentconfigurationoneffectivethermalconductivity(ETC).Basedupontheproposedtheory,aconstructstrategywasdevelopedfordesigningtheETCbyalteringtheequivalentinteractionanglewiththedirectionofheatflow:relativelysmallaverageinteractionangleforthermalconductionandrelativelylargeoneforthermalinsulation.

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简介：NanofluidswerepreparedbydispersingCunanoparticles(~20nm)inn-tetradecanebyatwo-stepmethod.Theeffectivethermalconductivitywasmeasuredforvariousnanoparticlevolumefractions(0.0001-0.02)andtemperatures(306.22-452.66K).TheexperimentaldatacompareswellwiththeJangandChoimodel.Thethermalconductivityenhancementwaslowerabove391.06Kthanforthatbetween306.22and360.77K.Theinterfacialthermalresistanceincreasedwithincreasingtemperature.Theeffectivethermalconductivityenhancementwasgreaterthanthatobtainedwithamoreviscousfluidasthebasemediaat452.66KbecauseofnanoconvectioninducedbynanoparticleBrownianmotionathightemperature.

简介：Weinvestigatetheinteractionbetweenapositivemassandanegativeeffectivemassthroughathreemasschainconnectedwithelasticsprings,apairofmassesisdesignedtohaveaneffectivenegativemass,anditinteractswiththethirdpositiveoneasifanequivalenttwo-masschain.Thedynamicsoftheequivalenttwo-masschainshowsthatthetwobodiesmaybeself-acceleratedinsamedirectionwhentheeffectivemassbecomesnegative,theexperimentisalsoconductedtodemonstratethistypeofmotion.Wefurthershowthattheenergyprinciple(Hamilton’sprinciple)isapplicableiftheenergyofthenegativemassunitisproperlycharacterized.Theresultmayberelevanttocompositewithcellsofeffectivenegativemass,theirinteractionwithmatrixmayleadtomorericherunexpectedmacroscopicresponses.

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