学科分类
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186 个结果
  • 简介:Thispaperstudiesthechemicalcomposition,tensileproperties,inclusions,metallogrophicstructure,andothersuchparameterstoidentifythecausesofcrackingduringthebendingofhigh-strengthsteel.Theresultsshowthatthemajorcausesofcrackingaretheoriginaltransversecracksorholesonthesurfaceoftheslabandthepresenceofscalesrolledintothecracksorholes.Coldfracturingfromsuchdefectsisrare,andcanbeeleminatedbyenhancingthecontrolofthesteelmakingprocessandbymechanicalclean-upofthesurfacecracksandholesintheslab.

  • 标签: 高强度钢板 弯曲过程 原因 实验 开裂 横向裂缝
  • 简介:Thereliabilityofsteelweldsbecomesmorecriticalissuewithincreasingsteelstrength,becausebrittlephasesaremorelikelytoformintheweldmetalsandheat-affectedzone(HAZ)andtherebythetoughnessandductilityoftheweldsaredegraded.Therefore,refinementofmicrostructureandminimizationofthebrittlephasesarenecessarytoimprovethereliabilityofthehigh-strengthsteelwelds.Inthispresentation,microstructureformationthatcontrolsthetoughnessofweldmetalsandHAZinhigh-strengthlow-alloy(HSLA)steelweldsisreviewedandpossibleroutestotheimprovementoftheweldmicrostructureandweldtoughnessarediscussed.

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  • 简介:Themechanicalperformanceofcarbonnanotube(CNT)reinforcedpolymercompositesisprimarilycontrolledbythedispersivecapacityandinterfacialshearstrengthofCNTsinpolymermatrices.CNTfunctionalizationswillimprovedispersionandstrengtheninterfacialbondingofCNTsinmatrices.TounderstandtheeffectsofdifferentfunctionalizationschemesontheinterfacialstrengthofCNT-polymercomposites,pulloutofthecovalent,noncovalent,andmixedfunctionalizedsingle-walledcarbonnanotube(SWCNT)frompolyethylene(PE)matrixwassimulatedbyusingmoleculardynamics,respectively.TheresultsshowthattheSWCNT-PEinterfacialshearstrengthissignificantlyimprovedbySWCNTfunctionalizations,particularlybymixedfunctionalization.

  • 标签: 单壁碳纳米管 聚乙烯复合材料 界面强度 功能化 聚合物复合材料 界面剪切强度
  • 简介:Inthisstudy,a600MPahot-rolledcorrosion-resistantsteelplateproducedbyaspecificcompanyisinvestigated.Edgejaggeddefectsandedgesurfacedefectsgeneratedonbothsidesofthestripduringproductionarecharacterizedandanalyzed.Theresultsindicatethatthedistributionofreoxidationgranulesislocatedunderneaththesurfacepeelandthatcopper-containinggranulesdiffusealongaustenitegrainboundaries.Thisphenomenoncombinedwiththechemicalcompositionandproductionparametersofastripindicatethatcopperbrittlenessleadstoedgejaggeddefects.However,thesurfacedefectsshouldbeattributedtoinherentdefectsonthesurfaceofthestrip.Measuresthatpreventsurfaceoxidationandcoppersegregationatgrainboundarieswouldlikelyeliminatethesetwotypesofedgedefects.

  • 标签: 缺陷分析 耐腐蚀钢 高强度 表面缺陷 生产过程 晶界扩散
  • 简介:ThehotrollingexperimentinvestigatesintotherelationshipbetweenthemicrostructuresandthemechanicalpropertiesofNb-TimicroalloyedsteelswithvariousTicontents.TheresultsindicatethattheeffectofthebainitefractionofNb-TimicroalloyedsteelsontheyieldstrengthofthesteelsisnotrelatedtoTicontent,whiletheslopeoftheHall-PetchrelationshipdecreaseswiththeincreaseofTicontent.Accordingly,theMisramodelfortheyieldstrengthofNb-Timicroalloyedsteelsismodified,andthefactorswhichcausethechangeintheslopeofHall-Petchrelationshiparediscussed.

  • 标签: 微合金化钢 屈服强度 钛含量 铌钛 力学性能 微观组织
  • 简介:Theearthquake-resistantpropertyofreinforcedconcretemembersdependsontheinteractionbetweenreinforcingbarsandsurroundingconcretethroughbondtoalargedegree.Inthispaperageneralsystemaimedatdealingwiththefailureanalysisofreinforcedconcretecolumnsstrengthenedwithcarbon-fiber-reinforcedplastic(CFRP)sheetsincludingbond-slipoftheanchoredreinforcingbarsatthefootofthecolumnsispresented.Itisbasedontheyielddesigntheorywithamixedmodelingofthestructure,accordingtowhichtheconcretematerialistreatedasaclassicaltwo-dimensionalcontinuum,whereasthelongitudinalreinforcingbarsareregardedasone-dimensionalrodsincludingbond-slipatthefootofthecolumns.InshearreinforcedzonesboththeshearCFRPsheetsandtransversereinforcingbarsareincorporatedintheanalysisthroughahomogenizationprocedureandtheyareonlyintension.Theapproachisthenimplementednumericallybymeansofthefinite-elementformulation.Thenumericalprocedureproducesaccurateestimatesfortheloading-carryingcapacityoftheshearmemberstakenasanillustrativeapplicationbycorrelationwiththeexperimentalresults,sotheproposedapproachisvalid.

  • 标签: 钢筋混凝土柱 碳纤维增强塑料板 玻璃钢板 剪切强度 数值计算 地震激励
  • 简介:Areasonablestrengthcriterionshouldreflectthehydrostaticpressureeffect,minimumprincipalstresseffect,andintermediateprincipalstresseffect.Theformertwoeffectscanbedescribedbythemeridiancurves,andthelastonemainlydependsontheLodeangledependencefunction.Amongthreeconventionalstrengthcriteria,i.e.Mohr–Coulomb(MC),Hoek–Brown(HB),andExponent(EP)criteria,thedifferencebetweengeneralizedcompressionandextensionstrengthofEPcriterionexperienceafirstlyincreasethendecreaseprocess,andtendstobezerowhenhydrostaticpressureisbigenough.Thisisinaccordancewithintrinsicrockstrengthcharacterization.Moreover,thecriticalhydrostaticpressureIccorrespondingtothemaximumdifferenceofbetweengeneralizedcompressionandextensionstrengthcanbeeasilyadjustedbyminimumprincipalstressinfluenceparameterK.So,theexponentfunctionisamorereasonablemeridiancurves,whichwellreflectsthehydrostaticpressureeffectandisemployedtodescribethegeneralizedcompressionandextensionstrength.Meanwhile,threeLodeangledependencefunctionsofLMN,LWW,andLYMH,whichunconditionallysatisfytheconvexityanddifferentialrequirements,areemployedtorepresenttheintermediateprincipalstresseffect.Realizingtheactualstrengthsurfaceshouldbelocatedbetweenthegeneralizedcompressionandextensionsurface,newtrue-triaxialcriteriaareproposedbycombiningthetwostatesofEPcriterionbyLodeangledependencefunctionwithasamelodeangle.Theproposednewtrue-triaxialcriteriahavethesamestrengthparametersasEPcriterion.Finally,14groupsoftriaxialtestdataareemployedtovalidatetheproposedcriteria.Theresultsshowthatthethreenewtrue-triaxialexponentcriteria,especiallytheExponentWillam-Warnkecriterion(EPWW)criterion,givemuchlowermisfits,whichillustratesthattheEPcriterionandLWWhavemorereasonablemeridiananddeviatoricfunctionform,respectively.Theproposednewtrue-tria

  • 标签: Rock Strength criterion MERIDIAN plane Lode
  • 简介:ThenanostructuredAl-basedcompositespossessthecombinationofhighyieldstrengthandgoodductility.Inthispaper,amicromechanicalmodelispresentedtosimulatethemechanicalresponseofbimodalnanostructuredAlandtheparticle-reinforcedaluminummatrixcomposite(PAMC).Theconstitutiverelationsfordifferentphasesareaddressedinthemodel,aswellasthecontributionofmicrocracks.NumericalresultsshowthatthemodelcansuccessfullydescribetheenhancedstrengthandductilityofthebimodalnanostructuredAl,andthepredictionsofthePAMCareingoodagreementwiththeexperimentaldata.ItisworthnotingthatthestrengthandductilityaresensitivetothevolumefractionofconstituentsandthedistributionofmicrocracksinbothbimodalnanostructuredAlandPAMC.Therefore,thepresenttheoreticalresultscanbeusedtooptimizethemicrostructureforimprovingthemechanicalpropertiesofnanostructuredAl-basedcomposites.

  • 标签: 颗粒增强铝基复合材料 屈服强度 纳米材料 细观模拟 聚丙烯酰胺水凝胶 塑性
  • 简介:与一个简单索引定义东方亚洲冬季季风(EAWM)的紧张是一项困难的任务。这份报纸在18存在EAWM力量索引的意思上详细描述并且分类他们进四个范畴:低级的风索引,上面的带的风砍索引,东方西方压力对比索引,和东方亚洲人马槽索引。索引当时是的这些的时间/空间的表演和预言潜力为1957鈥?分析了001时期。它表明在十的timescale上,除了东方西方压力的大多数索引对比索引能很好捕获在1986附近的EAWM的连续变弱。在interannualtimescale上,低级的风索引和东方亚洲马槽索引基于ElNi的知识有最好的可预测性?o南部的摆动和北极摆动分别地。所有18个存在索引能很好描述EAWM相关的发行量,降水,和更低的tropospheric空气温度异例。然而,在华中的大区域上的表面空气温度的变化不能与地志的效果有关可能是大多数索引捕获的井,它是。这研究的结果可以为EAWM的未来研究提供一本可能的参考书。关键词东方亚洲冬季季风索引-interannual变化-interdecadal变化

  • 标签: 东亚冬季风 季风强度 年际时间尺度 东亚大槽 压力对比 可预测性
  • 简介:关于mesomechanics的一个新方法有限元素的研究被建议预言山峰砍mesoscopic上的材料放大的mudded置闰的力量。基于几何、机械的参数,与样品获得的种类失败标准一起变丑特征,样品上的单轴的压缩测试通过一个有限元素的模型被模仿,它从单轴的压缩测试的实验室产出与数据一致的值,暗示方法是合理的。把模型基于这,一shear测试被执行计算山峰砍mudded置闰的力量,与在文学报导的价值一致,从而提供为调查mudded的机械性质的一条新途径置闰材料。

  • 标签: mudded 置闰 mesomechanics 有限元素的方法 mesoscale 结构 砍力量
  • 简介:Studiedtheeffectofionicstrengthontheuptakeoftaurineonastrong-basicanionexchangeresin.ThebatchphaseequilibriumexperimentsoftaurineontheanionexchangeresinD290wereconductedatdifferentionicstrength,andthentheamountsofuptakeoftaurineontheresinatdifferentpHweredetermined.TheionexchangemechanismsoftaurineontheanionexchangeresinatdifferentpHwerediscussed.Experimentalresultsshowedthatwithincreaseoftheionicstrengthofsolution,theadsorbedamountoftaurineontheresinD290decreased;AddingsmallamountsofNaOHorHClintothesystemoftaurineaqueoussolution/D290anionresinwouldmaketheamountoftaurinetakenupontheresintodecreaseduetothecompetitionuptakesofhydroxylionwithtaurineorthedecreaseintheamountofabsorbablezwitterionsoftaurineinthesolutionandexcludingthecationsoftaurinefromtheanionresin.

  • 标签: 阴离子交换树脂 牛磺酸 pH值 分离 交换机理
  • 简介:Theproductionindexesweredeterioratedduetoqualitycoke,UtilizationFactor2.0t/m3·d,PCI100kg/T,AccordingtoAnalysistheMechanismofProductionoflowhotstrengthcokequalityonBlastFurnaceSmooth,ThecokecoldstrengthretainedM10<6.3overalongperiodoftimeinordertoinsurecokegranularityandpermeabilityindexincohesivezone;Aad<12andgranularitytranquilizationisusefulBFproduction.ThePCIprotectcokehotstrengthbyhighratebituminouscoals;highrateH2inBFgasbatecokedemolish.blastfurnaceoperation,onmonitoringandoperationBF,tranquilizationtheBLASTFURNACEtemperature,PTcontrolsparameterareaisabout1500℃;strengthenmanagementofpermeabilityindex,improveTop-pressureforBlastFurnace,StrengtheningtheManagementoftheRawMaterialsandFuel,logicalrateofsinterLeveloffabout70%toimproveMetallurgicalPropertiesofBurdens.ParametersofwindhavebeenadoptedAbout10000-11000kg·m/s;,theoreticalflametemperatureinablastfurnacehavebeenadjustedareaisabout2050-2200℃;thetemperaturedirectionaboutcopperstavemanagementestablishedact;accordingtothismeasures,AccordingtoImprovementCenterGasFlowInstabilityinthefirstplace,thegasflowdistributionturnstothereasonablestate.Strengthenfurnacecasthouseoperationect,UtilizationFactorimprove2.2t/m3·d,PCI130kg/T.ColdandhotstatestrengthindexesofcokeonBFproductionwereinstability.AccordingtooptimizetheOperatingParameteinspecificallyeconomytechnologyindexesconduction,theBFcondictioncankeepingsteadyandsmooth.

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  • 简介:Fromtheviewpointofweldingmechanics,twonewweldingmethods-weldingwithtrailingpeeningandweldingwithtrailingimpactiverollingwereintroduced.Foraluminumalloythin-shellstructureswithhighstrength,weldingwillleadtohotcracking,poorjointanddistortion.Inordertosolvethem,trailingimpactivedevicewasusedbehindweldingtorchtoimpactthedifferentpositionsofweldedjoints,thusrealizingtheweldingwithfree-hotcracking,lowdistortionandjointstrengthening.Byuseofimpactiverollingwheelsinsteadofpeeningheads,theoutlookofweldedspecimencanbeimprovedandstressconcentrationatweldtoescanbereduced.Equipmentofthistechnologyissimpleandportable.Itcanusedtoweldsheets,longitudinalandring-likebeamsoftube-likestructures,aswellasthethin-shellstructureswithclosedweldssuchasflangesandhatches.Sothetechnologyhasthewideapplicationforegroundinthefieldsofaviationandaerospace.

  • 标签: 铝合金 薄板 焊接 航空 变形
  • 简介:Theadditionofahardenerisnecessaryforthecuringofurea-formaldehyde(UF)adhesivesintheproductionofMDFandparticleboard.Themostcommonlyusedhardener,ammoniumchloride,however,issuspectedtocausetheformationofpoisonousdioxinwhenwasteboardsarecombustedandhenceconsideredasapotentialsourceofpollution.Toassessthefeasibilityofsubstitutingammoniumsulphateforammoniumchloride,workingpropertiesandbondingstrengthweremeasuredforUFadhesiveswiththetwo...

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  • 简介:Theblastresistanceofstructuresusedinbuildingsneedstobeinvestigatedduetotheincreasedthreatofaterroristattack.ThedamagedonebyCompositionBorPowergeltosteelfibrereinforcedreactivepowderconcrete(SFRPC)panelsandordinaryreinforcedconcrete(RC)panelsofequivalentstaticflexuralstrengthiscompared.A0.5kgchargewasdetonatedatadistanceof0.1mfromthe1.3m×1.0m×0.1m(thick)panels,whichweresimplysupportedandspaning1.3m.Dynamicdisplacementmeasurements,high-speedvideorecordingandvisualexaminationofthepanelsforspallandbreachwereundertaken.TheSFRPCpanelswithstoodthebarechargeblastbetterthanthereinforcedordinaryconcretepanels.Neithertypeofpanelwasbreachedusinga0.5kgcharge.TheRCpanelexhibitedmorespallingwhenCompositionBwasused.UndersuccessiveCompositionBloadingconditions,theRCpanelwasbreached.IncomparisontheSFRPCpanelwasnotbreached.ExposuretofragmentingchargeloadingconditionsconfirmedtheseperformancedifferencesbetweentheSFRPCpanelandthereinforcedordinaryconcretepanel.

  • 标签: 钢铁纤维增强粉末混凝土 爆破载荷 剥落 建筑物 安全保护
  • 简介:BycombiningtheB-splinebasissetwithmodelpotential(B-spline+MP),wepresentoscillatorstrengthspectraofRydbergLiatomsinexternalfields.Thephotoabsorptionspectraareanalyzed.Overthenarrowenergyrangesconsideredinthispaper,thestructureofthespectracanbeindependentoftheinitialstatechosenforagivenatom.Ourresultsareingoodagreementwithprevioushigh-precisionexperimentaldataandtheoreticalcalculations,wheretheR-matrixapproachtogetherwithmultichannelquantumdefecttheory(R-matrix+MQDT)wasused.ItissuggestedthatthepresentmethodscanbeappliedtodealwiththeoscillatorstrengthspectraofRydbergatomsincrossedelectricandmagneticfields.

  • 标签: 里德伯原子 振子强度 模型势 计算 多通道量子亏损理论 矩阵方法
  • 简介:Theinterfacialbindingcovalentbonddensity(CBD)andthelocalenvironmentaltotalbondorder(LTBO)oftheNi/Ni3Alinterfacewithdifferentlatticemisfits(δ)werecalculatedbyusingfirst-principlesdiscretevariationXαmethod.ItwasfoundthattheeffectsoflatticemisfitsontheelectronicstructuresofincoherentNi/Ni3Alinterfacewereveryobvious.Ononehand,lessthan-0.6%negativelatticemisfitcanpromotethebindingstrengthofγ/γ′interface.Ontheotherhand,thetotalbondingstrengthofγ/γ′interfacedecreaseswithincreasingδ.Therefore,themagnitudeandsignoflatticemisfitmustbecarefullycontrolledforbalancingthehightemperaturecreepstrengthofNi-basesinglecrystalsuperalloyandthestructuralstabilityofγ/γ′interfacewhenonedesignsanewNi-basesinglecrystalsuperalloy.

  • 标签: γ/γ′ interface LATTICE misfit DV-Xα method