简介：Grapheneisthestrongestmaterialbutitsperformanceissignificantlyweakenedbyvacancydefects.Weusemoleculardynamicssimulationstoinvestigatethetensilebehaviorofagraphenewhichcontainsasinglevacancydefect.Ourresultssuggestthatbecauseofthesinglevacancy,thefracturestrengthofgraphenelossesabout17.7%.Thestressconcentrationaroundthevacancydefectleadstothedestructionofnearbysix-memberringsstructure,whichformstheinitialcrack.Thepropagationdirectionofthiscrackindefectivegrapheneisatanangleof60°tothetensiledirectioninitially,butthenbecomesperpendiculartothetensiledirection.

简介：Thegeometricshapesofspecimensareimportantinimpacttensiletestsbecausegeometricshapesdeterminethestressstatesofthespecimens,andprecisegeometricshapescanobtainpropermaterialpropertieswithoutnon-materialfactors.Theaimofthisstudywastoinvestigatethe1Dformofthestressbychangingthelength-to-diameter(L/D)ratiosofspecimens.TheexperimentswerecarriedoutonasplitHopkinsontensilebar(SHTB)-rotatingdiskindirectbar-bartensileimpactapparatus.TheL/DratiosoftheLY12CZspecimensusedinthetestrangedfrom1to5.ResultsshowthatthespecimenscanbeusedtoobtainexactparametersofmaterialsundertheproposedconditionswhentheL/Dratioisgreaterthan2.Thisisbecausethelongerlengthwillreduceoreliminatetheeffectsoftheinterfaces.

简介：InordertoaccomplishreliablemechanicaldesignofMEMS,theinfluencesofsurfaceroughnessandoctadecyltrichlorosilane(OTS)self-assembledmonolayers(SAMs)onthemechanicalpropertiesofmicromachinedpolysiliconfilmsforMEMSareinvestigated.Surfaceeffectonthefracturepropertiesofmicromachinedpolysiliconfilmsisevaluatedwithanewmicrotensiletestingmethodusingamagnet-coilforceactuator.Statisticalanalysisofthesurfaceroughnesseffectsonthetensilestrengthpredicatedthesurfaceroughnesscharacterizationofpolysiliconfilmsbeingtestedandthedirectrelationofthemechanicalpropertieswiththesurfaceroughnessfeatures.Thefracturestrengthdecreaseswiththeincreaseofthesurfaceroughness.Theoctadecyltrichlorosilaneself-assembledmonolayerscoatingleadstoanincreaseoftheaveragefracturestrengthupto32.46%.SurfaceroughnessandthehydrophobicpropertiesofspecimenwhencoatedwithOTSfilmsarethetwomainfactorsinfluencingthetensilestrengthofmicromachinedpolysiliconfilmsforMEMS.

简介：Tostudythemechanicalpropertiesofthefilm/substratestructure,thefiniteelementcodeABAQUSv6.9-1isadoptedtosimulatethetensilemechanicalbehaviorofthenanoscalethinfilmbondedtoasubstrate.Thebifurcationphenomenonofthestructureunderuniaxialtensionisfound:thesingle-neckdeformation,themultiple-neckdeformationandtheuniformdeformation.Thesubstrateandthefilmareregardedaspower-hardeningmaterialsobeyingtheJ2deformationtheory.Firstly,theinfluenceofmaterialhardeningmatchontensilebifurcationmodeisanalyzedunderperfectlywell-bondedinterfacecondition.Then,theeffectsofinterfacialstiffnessandothersuperficialdefectssurroundingtheimperfectiononbifurcationmodeareinvestigated.Itisconcludedthatunderthewell-bondedinterfacecondition,ifthestressofthesubstrateislargerthanthefilm,thefilmwilluniformlydeformwiththesubstrate;ifthestressofthesubstrateissmallerthanthefilm,thefilmwillformasingleneck,exceptthecasethataweakly-hardeningfilmisbondedtoasteeply-hardeningsubstratewhenmultipleneckscanbeformed.Withthedecreaseofinterfacialstiffness,theuniformdeformationmodecantransformintothemultiple-neckdeformationmode,andfurthertransformintothesingle-neckdeformationmode.Andotherdefectssurroundingtheimperfectioncaninfluencethewavelengthofdeformationandnecknumber.

简介：Thetensile-shearfailurezoneofthelaminateddampingsteelsheetwasinvestigatedbyscanningelectronmicroscopyandX-rayphotoelectronspectroscopy.Itisfoundthatthereexistscohesivefailureinpolymersandwichandsub-boundaryfailurebetweenthesteelsheetandthepolymer.Thesub-boundarylayerisdominantlypolymermaterial.Thetensile-shearfailureofthelaminateddampingsteelsheetisaprocessduringwhichthecrazesform,growupandmergeintocracks.

简介：Three-dimensionaledgecracksareanalyzedusingtheSelf-SimilarCrackExpansion(SSCE)methodwithaboundaryintegralequationtechnique.TheboundaryintegralequationsforsurfacecracksinahalfspacearepresentedbasedonahalfspaceGreen’sfunction(Mindlin,1936).ByusingtheSSCEmethod,thestressintensityfactorsaredeterminedbythecrack-openingdisplacementoverthecracksurface.Indiscreteboundaryintegralequations,theregularandsingularintegralsonthecracksur-faceelementsareevaluatedbyananalyticalmethod,andtheclosedformexpressionsoftheintegralsaregivenforsubsurfacecracksandedgecrakcs.Thisgloballynumericalandlocallyanalyticalmethodim-provesthesolutionaccuracyandcomputationaleffort.Numericalresultsforedgecracksundertensileloadingwithvariousgeometries,suchasrectangularcracks,ellipticalcracks,andsemi-circularcracks,arepresentedusingtheSSCEmethod.Resultsforstressintensityfactorsofthosesurfacebreakingcracksareingoodagreementwithothernumericalandanalyticalsolutions.

简介：Thebendingstrengthofmicrofabricatedpolysiliconbeamswasmeasuredbybeambendingusingananoindenter.Also,thetensilestrengthofmicrofabricatedpolysiliconthinfilmswasmeasuredbytensiletestingwithanewmicrotensiletestdevice.Itwasfoundthatthebendingstrengthandtensilestrengthofpolysiliconmicrostructuresexertssizeeffectonthesizeofthespecimens.Insuchcases,thesizeeffectcanbetracedbacktotheratioofsurfaceareatovolumeasthegoverningparameter.Astatisticalanalysisofthebendingstrengthforvariousspecimensizesshowsthattheaveragebendingstrengthofpolysiliconmicrocantileverbeamsis2.885±0.408GPa.ThemeasuredaveragevalueofYoung'smodulus,164±1.2GPa,fallswithinthetheoreticalbounds.Theaveragefracturetensilestrengthis1.36GPawithastandarddeviationof0.14GPa,andtheWeibullmodulusis10.4-11.7,respectively.Thetensiletestingof40specimensonfailureresultsinarecommendationfordesignthatthenominalstrainbemaintainedbelow0.0057.

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。

简介：MagnesiumalloyEZ10(Mg-RE-Zn)wasdeformedintensionattemperaturesfrom20upto520°C.Arapiddecreaseoftheyieldandtensilestrengthwithtemperaturewasobservedattemperatureshigherthan300°C.Ontheotherhand,ductilityofsamplesrapidlyincreasedinthesametemperaturerange.Lightmicroscopyandscanningelectronmicroscopywasusedtorevealthereasonforthesebehaviours.Intermetallicparticlesingrainboundariesareresponsibleforexcellentmechanicalpropertiesatlowertemperatures.Diffusionalprocessesoccurringattemperatureshigherthan300°Csignificantlyinfluencedthedeformationmechanismaswellasthefracturecharacter.

简介：Threedifferenttypesoftensilestrength(TS)980MPagradeadvancedhigh-strengthsteelsusedinautomotiveapplications,namely,980MS(martensitesteel),980DP(dualphase)and980QP(quenchingandpartitioning)steelswereexamined.ThedelayedfractureresistanceofthesteelswasevaluatedusingaU-bendtest,slowstrainratetest(SSRT)andaconstantloadtensiletest.Theresultsindicatedthatallthesteelscouldpassthe300hHClsolutionimmersiontestandnoneoftheU-bendspecimenswasfracturedinthetest.However,thesteelsexhibiteddifferentsusceptibilitiestodelayedfractureunderSSRTandtheconstantloadtensiletests.980DPexhibitedthehighestresistancetodelayedfractureamongallthesamples,while980MSwasfoundtobethemostsusceptibletodelayedfracture.

简介：Titaniumandtitaniumalloyshaveseveraladvantages,butthecostoftitaniumalloysisveryexpensivecomparedwiththetraditionalmetalmaterials.Thisarticleintroducestwonewlow-costtitaniumalloysTi-2.1Cr-1.3Fe(TCFalloy)andTi-3Al-2.1Cr-1.3Fe(TACFalloy).Inthisstudy,weusedCr-Femasteralloyasoneoftherawmaterialstodevelopthetwonewalloys.Weintroducethemicrostructureandtensilepropertiesofthetwonewalloysfromβsolutiontreatedwithdifferentcoolingmethods.Optica...

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简介：TensileimpactexperimentsofEC8.0-24×7glassfiberbundlesatdifferentlowtempera-turesT（14℃,-40℃and-100℃）andstrainratesεwerecarriedout,andcompletestress-straincurveswereobtained.Withintherangeoftheexperimenttemperaturesandstrainrates,itisfoundthattheinitialmodulusE,theultimatestrengthσmaxandtheunstablestrainεboftheglassfiberbundlesallincreasewithatanidenticalT.Atanidenticalε,withthedecreaseofT,Eandσmaxincrease;butεbincreaseswhen14℃>T>-40℃anddecreaseswhen-40℃>T>-100℃.Thestrain-rate-andtemperature-depen-dentbimodalWeibullstatisticalconstitutivetheorywasadoptedforthestatisticalanalysisoftheexperimentalresults,andtheWeibullparametersofsinglefiberwereobtained.TheresultsshowthatthebimodalWeibulldistributionfunctionissuitabletorepresentthestrengthdistributionoftheglassfiberatlowtemperatureanddifferentstrainrates.ThedifferencesinthemechanicalpropertiesbetweenEC8.0-24×7andEC5.5-12×14glassfiberbundleswerealsodiscussed.

简介：分层的钢纤维增强了橡胶水泥(LSFRRC)，基于国家标准的要求具体的人行道的一种新类型试验性地被研究。从平凡水泥(PC)的曲折张力的力量的不同性质，橡胶水泥(RC)，分层的钢纤维增强了水泥(LSFRC)，LSFRRC被介绍。试验性的结果与RC相比证明LSFRRC的张力的力量被4.12%与PC相比改进，在13.75%。曲折张力的性质上的负担偏转曲线被提出。LSFRRC的曲折张力的坚韧索引I10与PC相比被改进10.32次。

简介：微观结构和Ni//3艾尔的机械性质基于拥有低杂质内容的Ni-Al-Mosuperalloy-IC6，由水花免职技术的高密度被学习了。结果显示IC6合金在空间和中间的温度两个都有好张力的力量和延伸。(编辑作者摘要)6个裁判员。

简介：Theeffectofcathodichydrogenchargingonthetensileandconstantloadpropertieswasdeterminedforanausteniticstainlesssteelweldmentcomprisinga304Lsteelinthesolutiontreatedconditionasabasemetalanda308Lfillersteelasaweldmetal.Partofthe304Lsolutiontreatedsteelwasseparatelygivenadditionalsensitizationtreatmenttosimulatethemicrostructurethatwoulddevelopintheheataffectedzone.Testswereperformedatroomtemperatureonnotchedroundbarspecimens.Hydrogenchargingresultedinapronouncedembrittlementofthetestedmaterials.Thiswasmanifestedmainlyasaconsiderablelossinthedluctilityoftensilespecimensandadecreaseinthetimetofailureandthresholdstressofconstantloadspecimens.The308Lweldmetalexhibitedthehighest,andthe304Lsolutiontreatedsteelthelowest,resistancetohydrogenembrittlement.Hydrogenembrittlementwasassociatedwiththeformationofstraininducedmartensiteaswellasatransitionfrombrittletoductilefracturemorphologyonwardsthecentreofthespecimens.

简介：Estrogendeficiencyhasbeenproposedasariskfactorforalveolarboneloss,butwhetherornotestrogenwillinflucencethebonerebuiltingprocessduringorthodontictoothmovementandwhatthemechanismsinvolvedremainunclear.Thepaperaimstoprovidenewinformationthatmayelucidatethemodulatoryeffectofestrogenonthebone-resorbingcytokinesRANKLanditsanti-resorptivefactorOPGsecrectedbyHPLFswhicharealreadyforce-stimulated.TheexpressionofOPGmRNAisrisingaftermechanicalloadingeitherwithorwithoutstimulatedbyestrogenbefore.ButHPDLcellsexposuredtoestrogenfor24hbeforeloadedtendtoexpressmoreOPGmRNA.Comparedwiththeno-estrogengroup,theinhibittrendofRANKLmRNAismuchmoreapparentinwith-estrogengroup.Moreover,estrogenandmechanicforcetime-dependentlyincreasedOPGexpressionandattenuatedtheRANKLexpression.

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简介：Invitrocellloadingexperimentsareusedtoinvestigatestimulationofstraintocellularproliferation.Astheflowingconditionsofculturefluidinloadingsystemshasbeenlittleknown,strictlypeoplecannotdetecttheinfluenceofstraintocellularproliferationexactlybecauseshearflowcanenhancecellproliferationeither.Basedontheworkingprincipleandcyclicloadingparameters,wesimplifyNavier-Stokesequationtodescribetheflowofculturefluidonsubstratesofuniaxialandequi-biaxialfiattensileloadingsystemsandfourpointbendingsystem.Withapproximatesolutions,thedistributionsofvelocityfieldandwallshearflowtocellsaregained.Resultsshow:shearflowsarezerointhemiddle(orfixedpointorline)ofsubstrateforallsystems,andtheygetlargerproportionallytodistancefrommiddleandsubstrateelongate;theshearflowonthesubstrateoffourpointbendingsystemismuchgreaterthanthoseofothers.Thisshearflowinfourpointbendingsystem,confirmedbyOwan,I.,etalwithOPNmRNAincreaseintheirexperiment,couldcausemoreinfluencetoosteoblast-likecellsthanthatcausedbystrain.WeestimatetheaveragemagnitudeofshearstressinOwan'sdevice,theresultsareconsistentwithotherexperimentaldataaboutshearflow.Inconclusionourstudymakesitpossibletodifferentiatetheinfluenceofstrainoncellularproliferationtothatofshearflowinloadingexperimentswiththedevicesmentionedabovequantitatively.