简介：Thispaperdemonstratestheplanestressstateandthestressfreethermo-elasticdeformationofFGMthickplateunderthermalloading.First,theSneddon-LocketttheoremontheplanestressstateinanisotropicinfinitethickplateisgeneralizedforacaseofFGMprobleminwhichallthermo-mechanicalpropertiesareoptionalfunctionsofdepthco-ordinate.TheproofisbasedonapplicationoftheIljushinthermo-elasticpotentialtodisplacementtypesystemofequationsthatreducesittotheplanestressstateproblem.Thenanexistenceofthepurelythermaldeformationisprovedintwoways:first,itisshownthattheuniquesolutionfulfilsconditionsofsimultaneousconstanttemperatureandlineargradationofthermalexpansioncoefficient,second,proofisbaseddirectlyonstresstypesystemofequationswhichstraightforwardlyreducestocompatibilityequationsforpurelythermaldeformationifonlystressfieldishomogeneousindomainandatboundary.Finally,coupleexamplesofapplicationtoanengineeringproblemarepresented.

简介：Thispaperpresentstwokinematicfailuremechanismsofthree-dimensionalrectangularfootingrestingonhomogeneousundrainedclayfoundationunderuniaxialverticalloadinganduniaxialmomentloading.ThefailuremechanismunderverticalloadingcomprisesaplanestrainPrandtl-typemechanismoverthecentralpartofthelongerside,andthesizeofthemechanismgraduallyreducesattheendsofthelongersideandovertheshortersideasthecornerofrectangularfootingisbeingapproachedwherethedirectionofsoilmotionremainsnormaltoeachcorrespondingsiderespectively.Thefailuremechanismundermomentloadingcomprisesaplanestrainscoopslidingmechanismoverthecentralpartofthelongerside,andtheradiusofscoopslidingmechanismincreaseslinearlyattheendsofthelongerside.Onthebasisofthekinematicfailuremechanismsmentionedabove,theverticalultimatebearingcapacityandtheultimatebearingcapacityagainstmomentormomentultimatebearingcapacityareobtainedbyuseofupperboundlimitanalysistheory.Atthesametime,numericalanalysisresults,Skempton'sresultsandSalgadoetal.'sresultsarecomparedwiththisupperboundsolution.Itshowsthatthepresentedfailuremechanismsandplasticlimitanalysispredictionsarevalidated.Inordertoinvestigatethebehaviorsofundrainedclayfoundationbeneaththerectangularfootingsubjectedtothecombinedloadings,numericalanalysisisadoptedbyvirtueofthegeneral-purposeFEMsoftwareABAQUS,wheretheclayisassumedtoobeytheMohr-Coulombyieldingcriterion.ThefailureenvelopeandtheultimatebearingcapacityareachievedbythenumericalanalysisresultswiththevaryingaspectratiosfromlengthLtobreadthBoftherectangularfooting.ThefailuremechanismsofrectangularfootingwhicharesubjectedtothecombinedverticalloadingVandhorizontalloadingH(VerticalloadingVandmomentloadingM,andhorizontalloadingHandmomentloadingMrespectivelyareobservedinthefiniteelementa

简介：Ananalyticalmodelisdevelopedtoassesstheelastic-plasticdynamicresponseoffullybackedsandwichplatesunderlocalizedimpulseload.Thecoreismodeledasanelastic-perfectlyplasticfoundation.Thetopfacesheetistreatedasanindividualplaterestingonthefoundation.Theelastic-plasticanalysisforthetopfacesheetisbasedonaminimumprincipleindynamicplasticityassociatedwiththefinitedifferencetechnique.Theeffectsofspatialandtemporaldistributionsoftheimpulsiveloadingonthedynamicresponseofsandwichplatesarediscussed.Themodelcanbeusedtopredicttheimpulse-inducedlocaleffectonfullybackedsandwichplates.

简介：Thispaperpresentsatheoreticalmodelonthenormal(head-on)collisionbetweensoft-spheresonthebasisofelasticloadingoftheHertzcontactforcompressionprocessandanonlinearplasticunloadingforrestitutionone,inwhichtheparametersallaredeterminedintermsofthematerialandgeometriconesofthespheres,andthebehaviorsofperfectelastic,inelastic,andperfectplasticcollisionsappearedintheclassicalmechanicsarefullydescribedonceavalueofcoefficientofrestitutionisspeci...

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简介：Fe/Cu/Cemodifiedcoal-basedactivatedcarbon(AC)waspreparedbythesol-gelmethod,andtheeffectofFe/Cu/CeoncatalyticpropertiesofFe/AC,Fe-Cu/ACandFe-Cu-Ce/ACwasinvestigatedinthehydrolysisofcarbonylsulfide(COS)at50°C.Theirsurfacepropertieswereevaluatedbymeansofnitrogenadsorptionandwerecharacterizedbyusingscanningelectronmicroscopy(SEM),X-raydiffracto-metry(XRD)andX-rayphotoelectronspectroscopy(XPS).ThecatalyticactivitiesresultsshowedthatadditionofCuandCe...

简介：Thepaperstudiestheproblemoffluidflowandfluidshearstressincanaliculiwhentheosteonissubjecttoexternalmechanicalloadingandbloodpressureoscillation.Thesingleosteonismodeledasasaturatedporoelasticcylinder.Solidskeletonisregardedasaporoelastictransverselyisotropicmaterial.Togetnear-realisticresults,boththeinterstitialfluidandthesolidmatrixareregardedascompressible.BloodpressureoscillationintheHaveriancanalisconsidered.Usingtheporoelasticitytheory,ananalyticalsolutionoftheporefluidpressureisobtained.Assumingthefluidincanaliculiisincompressible,analyticalsolutionsoffluidflowvelocityandfluidshearstresswiththeNavier-Stokesequationsofincompressiblefluidareobtained.Theeffectofvariousparametersonthefluidflowvelocityandfluidshearstressisstudied.更多还原

简介：Fatiguepropertiesofage-hardenedAlalloy2017-T4underultrasonicloadingfrequency(20kHz)wereinvestigatedandcomparedwiththeresultsunderconventionalloadingofrotatingbending(50Hz).Thegrowthofacrackretardedatabout500μminsurfacelengthunderultrasonicloading,whileatabout20μmunderrotatingbending.Althoughstriationsbeingatypicalfracturemechanismwereobservedunderconventionalloading,mostoffracturesurfacewascoveredwithmanyfacetsunderultrasonicloading.Thesefacetswerealsoobservedunderrotatingbendinginnitrogengas.Thedifferenceingrowthmechanismdependingontheloadingfrequencyandtheretardationofacrackgrowthunderultrasonicloadingmaybecausedbytheenvironmentatthecracktipduetohighcrackgrowthrateunderultrasonicloading.

简介：Themajorobjectiveofthisresearchwastodiscusstheeffectsofloadingrateontheflexural-tensionpropertiesanduniaxialcompressivestrengthofmicro-surfacingmixtureusingthree-pointbendingtestanduniaxialcompressivetestrespectively.Asapreventivemaintenancesurfacetreatmentonasphaltpavement,micro-surfacingwasformedonthebasisoftheISSArecommendationofanoptimummicro-surfacingdesign.Testswereconductedoverawiderangeoftemperaturetoinvestigatethedifferenceofpropertiesfromlowloadingratetoarelativelyhighloadingrate.Three-pointbendingtestwasusedtostudytheflexuralstrength,strainandmodulusofmicro-surfacingmixture,anduniaxialcompressivetestwascarriedouttoobtaintherelationshipbetweenstrengthandtheloadingrateaswellastemperature.Theexperimentalresultsshowedthatflexuralstrengthathighloadingratewaslargerthanthatatlowloadingrate.Theflexuralstrengthdifferencebetweenlowandhighloadingrateenlargedwhenthetemperaturerose.Theflexuralstrainathighloadingrateincreasedcomparedwithresultsofthelowloadingrate.Resultsoftheflexuralmodulusrevealedthatmicro-surfacingmixtureexhibitedbetteranti-crackingcharacteristicatlowtemperaturewhengivenarelativelylowloadingrate.Resultsofuniaxialcompressivetestrevealedthatthestrengthdifferenceofmicro-surfacingamongdifferentloadingratesincreasedwiththeincreaseoftemperature.Thelogarithmrelationshipbetweenthestrengthandloadingrateoverawiderangeoftemperaturewasobtainedtocomparetheexperimentalandpredictedvalues,whichresultinginareasonableconsistency.

简介：InthisworkweproposetoreplacetheGLPDhypo-elasticitylawbyamorerigorousgeneralizedHooke’slawbasedonclassicalmaterialsymmetrycharacterizationassumptions.ThislawintroducesinadditiontothetwowellknownLame’smoduli,fiveconstitutiveconstants.AnanalyticalsolutionisderivedfortheproblemofasphericalshellsubjectedtoaxisymmetricloadingconditionstoillustratethepotentialoftheproposedgeneralizedHooke’slaw.

简介：绝缘的弹性体(DE)的表演变换器被粘弹性的导致松驰的机电的驱散显著地影响。这份报纸论述试验性的研究获得受到的DE膜(VHBTM9473)的率依赖者压力段关系纯象同时装载并且电的装载一样砍。拉长率依赖者行为被观察。当电压增加，结果也证明张力的力量减少。观察与由DE的一个粘弹性的模型的预言相比。这个实验可以被用于DE的动态机电的联合性质的进一步的研究。

简介：有双阶段的结构(alpha+beta)的alpha钛和它的合金在大约10~的紧张率下面动态地被使变形4s~(-1)。形成和微结构进化局部性砍乐队们被扫描电子显微镜学(SEM)和传播电子显微镜学(TEM)描绘。结果表明紧张和紧张率应该同时被看作机械条件为砍乐队形成，和twinning是变丑的一个重要模式。试验性并且在乐队以内的材料经历了的计算表演超高频率的紧张率(9X10~5s~(-1))变丑，它是平均紧张率的二大小要求了为砍乐队形成；在乐队的脱臼能被压缩并且发展成房间结构；到在乐队以内的alpha_2的阶段转变fromalpha被观察，并且转变产品(alpha_2)与他们的父母一起有某个结晶的取向关系；有在在乐队以内观察的直径的10亩m的一种平均尺寸的equiaxed谷物被建议是再结晶的结果。

简介：Parametricresonanceisoneofthemostimportantissuesinthestudyofdynamicalbehaviorofstructures.Inthispaper,dynamicinstabilityofamoderatelythickrectangularplateonanelasticfoundationisinvestigatedinthecaseofparametricandexternalresonancesduetoperiodicpassageofmovingmasses.Thegoverningcoupledpartialdifferentialequations(PDEs)ofthesystem,withconsiderationofthefirst-ordersheardeformationtheory(FSDT)orMindlinplatetheory,arepresentedandtheyarereducedtoasetofordinarydifferentialequations(ODEs)withtime-dependentcoefficientsusingtheGalerkinprocedure.Allinertialcomponentsofthemovingmassesareadoptedinthedynamicalformulation.Instabilitysurveyiscarriedoutforthreedifferentloadingtrajectoriesconsiderablyinterestedinmanypracticalapplicationsoftheissue,i.e.rectilinear,diagonalandorbitingtrajectories.Inordertoanalyzetheresonanceconditions,theincrementalharmonicbalance(IHB)methodisintroducedtocalculateinstabilityboundaries,aswellasexternalresonancecurvesinparametersplane.Acomprehensivestudyisdonetoassesseffectsofthicknessratioandfoundationstiffnessontheresonanceconditions.Itisfoundthatanincreaseintheplate'sthicknessratioleadstoareductioninvaluesofcriticalparameters.Moreover,itisobservedthatincreasingthefoundationstiffnessmovestheinstabilityregionsandresonaneecurvestohigherfrequenciesofthemovingmassesandalsoleadstofurtherstabilityoftheparametricallyexcitedsystematlowerfrequencies.TimeresponsesimulationsdoneviaRunge-KuttamethodconfirmedtheresultspredictedbyIHBmethod.

简介：Lithium-sulfur（Li-S）batteriesbelongtooneofthepromisingtechnologiesforhigh-energy-densityrechargeablebatteries.However,sulfurcathodessufferfrominherentproblemsofitspoorelectronicconductivityandtheshuttlingofhighlydissolublelithiumpolysulfidesgeneratedduringthecycles.Loadingsulfurintoporouscarbonshasbeenprovedtobeaneffectiveapproachtoalleviatetheseissues.Mesoporousandmicroporouscarbonshavebeenwidelyusedforsulfuraccommodation,butmesoporouscarbonshavepoorsulfurconfinement,whereasmicroporouscarbonsareimpededbylowsulfurloadingrates.Here,acore-shellcarbon,combiningboththemeritsofmesoporouscarbonwithlargeporevolumeandmicroporouscarbonwitheffectivesulfurconfinement,waspreparedbycoatingthemesoporousCMK-3withamicroporouscarbon（MPC）shellandservedasthecarbonhost（CMK-3@MPC）toaccommodatesulfur.Aftersulfurinfusion,theas-obtainedS/（CMK-3@MPC）cathodedeliveredahighinitialcapacityofupto1422mAh·g-1andsustained654mAh·g-1reversiblespecificcapacityafter36cyclesat0.1C.Thegoodperformanceisascribedtotheuniquecore-shellstructureoftheCMK-3@MPCmatrix,inwhichsulfurcanbeeffectivelyconfinedwithinthemeso/microporouscarbonhost,thusachievingsimultaneouslyhighelectrochemicalutilization.

简介：Theseeminglycontradictoryunderstandingsoftheinitialcrushstressofcellularmaterialsunderdynamicloadingsexistintheliterature,andacomprehensiveanalysisofthisissueiscarriedoutwithusingdirectinformationoflocalstressandstrain.Localstress/straincalculationmethodsareappliedtodeterminetheinitialcrushstressesandthestrainratesatinitialcrushfromacell-basedfiniteelementmodelofirregularhoneycombunderdynamicloadings.Theinitialcrushstressunderconstant-velocitycompressionisidenticaltothequasi-staticone,butlessthantheoneunderdirectimpact,i.e.theinitialcrushstressesunderdifferentdynamicloadingscouldbeverydifferenteventhoughthereisnostrain-rateeffectofmatrixmaterial.Apower-lawrelationbetweentheinitialcrushstressandthestrainrateisexploredtodescribethestrain-rateeffectontheinitialcrushstressofirregularhoneycombwhenthelocalstrainrateexceedsacriticalvalue,belowwhichthereisnostrain-rateeffectofirregularhoneycomb.Deformationmechanismsoftheinitialcrushbehaviorunderdynamicloadingsarealsoexplored.Thedeformationmodesoftheinitialcrushregioninthefrontofplasticcompactionwavearedifferentunderdifferentdynamicloadings.

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简介：基于1D波浪的特征，在在不同装载下面的标本的压力一致性进程调节矩形并且一半正弦输入波浪在裂口Hopkinson压力被分析工具条(SHPB)测试。结果证明从一个宣传的一个有弹性的波浪的时间在一个标本结束到其它达到压力平衡，与在标本和输入／输出酒吧之间的输入波形和相对机械阻抗有关。在此中与相对阻抗的increae，在装载的矩形的输入波浪下面的时间减少，当它在一半正弦输入下面增加时，飘动装载。相应于有相对机械阻抗的增加的压力平衡增加的地位的标本的尺寸更少压力价值。然而，在一半正弦输入波浪装载下面的尺寸更少压力值是比在矩形的输入波浪与低机械阻抗，和更少的应力不到二珍视随相对机械阻抗的增加装载条件减少的尺寸的相对差异为标本装载下面的值显著地低的。一般来说，有在一半正弦输入波浪装载下面的相对低的机械阻抗的标本的强迫的状态比在矩形的输入波浪在装载随相对机械阻抗的增加弱的拐弯的一半正弦输入波浪下面在强迫的状态的SHPB测试，和优点装载下面的状态显然优异。

简介：SixNi-MocatalystswithdifferentmetalcontentswerepreparedandcharacterizedbyN2adsorptionandX-raydiffractometry.TheactivephasemicrostructureofthesecatalystswasexaminedbytheRamanspectroscopy,temperatureprogrammedreduction(TPR),X-rayphotoelectronspectroscopy,andhigh-resolutiontransmissionelectronmicroscopy.Hydrodesulfurization(HDS)activityofcatalystsampleswereanalyzedinaflowfixed-bedmicroreactor.ThesulfidationdegreeofMoandthelengthoftheMoS2slabslightlyincreasedwiththeamountofmetalloadedfollowingsulfidation.Thissmallchangeisattributedtopolymolybdatespeciesobservedinalltheoxidizedcatalysts.Weakmetal-supportinteractions,asdeterminedbytheTPRtechnique,increasedtheNiSxsulfidationphaseandMoS2slabstacking.TheHDSactivityofthecatalystsamplesincreasedwiththenumberofactivesites.Forhighmetalloadingcatalysts,theirHDSactivitywasnearlyidenticalbecausethesulfuratomscannoteasilyapproachactivesites.ThischangeiscausedbythelargenumberofstackedlayersintheMoS2slabsaswellasthedecreaseinthespecificsurfaceareaandporevolumeofthecatalystsampleswithanincreasingmetalloading.

简介：Inthispaper,thebehavioroftwocollinearcracksinmagneto-electro-elasticcompositematerialunderanti-planeshearstressloadingisstudiedbytheSchmidtmethodforpermeableelectricboundaryconditions.ByusingtheFouriertransform,theproblemcanbesolvedwithasetoftripleintegralequationsinwhichtheunknownvariableisthejumpofdisplacementsacrossthecracksurfaces.Insolvingthetripleintegralequations,theunknownvariableisexpandedinaseriesofJacobipolynomials.Numericalsolutionsareobtained.Itisshownthatthestressfieldisindependentoftheelectricfieldandthemagneticflux.