学科分类
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8 个结果
  • 简介:Thedynamicresponseofastrain-softeningbeamsubjectedtoatransverseimpulsiveonitstipisinvestigated.Asofteningmoment-curvaturerelationisassumedforthebeamandaclosedformsolutionisobtainedforaspecialkindofload,whichshowsthatthereexistsasofteningregioninthebeamandthisre-gionpropagatesalongthebeam.Thisresultindicatesthat,exceptforthepossiblediscretesofteningpointswithrotationdiscontinuitycausedbythedeformationlocalization,theexistenceofthesofteningregionanditstravellingalongthebeamaretheessentialfeaturesofthedynamicresponseofastrain-softeningbeam.Theresultsalsoshowthatthefailureofthebeamshouldtakeplaceunderaspecialloadandthecriticalconditiononwhichthedynamicfailureoccursisgiven.

  • 标签: SOFTENING BEAM dynamic RESPONSE SOFTENING REGION
  • 简介:13kindsofironores(6fromAustraliaand7fromBrazil)werestudiedontheirpropertiesconcerningCW(CombinedWater)decomposition,Fe2O3decompositionandsoftening-meltinginairatmospherethroughthecharacterizationmethodofTG-DSC(Thermogravimetry-DifferentialScanningCaloremetry).TheexperimentalresultsoftheAustralianoresandBrazilianoresdifferintermsoftheinitialtemperature,temperaturerangeandendothermicamountofCWdecomposition,andbesides,thecontentofCW.ItisestimatedthatforeverypercentincreaseofCWcontentinsinteringrawmaterial,theextrathermalamountabsorbedintheprocessisabout1.83×104kJ,whichequalstothethermalcapacityof0.625kgofstandardcoalburningupcompletely.AstothedecompositionofFe2O3,theinitialtemperatures,terminaltemperaturesandtemperaturerangesoftheAustralianandBrazilianoresarequiteclose.However,theendothermicamountofFe2O3decompositionofthetwoturnsoutratherdifferent:theendothermiccapacityofFe2O3decompositionoftheAustralianoresisgreaterthanthatoftheBrazilianores.Furthermore,theliquidamountgeneratedinthesoftening-meltingprocessiscloselyrelatedtotheSiO2contentinironore.ThehigherSiO2contenttheorecontains,themoreliquidvolumeitwillgenerateinthesoftening-meltingprocessofironore.

  • 标签: TG-DSC 连续分解 铁矿石 熔化性能 软化 SIO2含量
  • 简介:Anapproximatemethodfordescribingtheplastichardening-softeningbehaviourofcircularpipessubjectedtopurebendingispresented.Theo-reticalestimationbasedontheuniformovalizationmodelandlocalcollapsemodelproposedinthepaperisincorporatedtogiveseveralsimpleformulationswithrea-sonableaccuracyfordeterminingtherelationshipbetweenbendingmoment(M)andcurvature(k)inthepurelybendedpipes.Attentionisfocusedonthecriticalcur-vatureassociatedwithmaximumresistantmomentandthemaximumchangeintheoriginaldiameterbeforetheendofuniformovalizationstageaswellasthelocalcollapsebehaviour.Somecomparisonsbetweenanalyticalresultsandexperimentalresultsaremadeinordertoexaminethetheory.

  • 标签: hardening-softening BEHAVIOUR pure bended PIPES circular
  • 简介:Onthebasisofplasticityandfracturemechanicsforquasi-brittlematerials,thisarticlepresentedaconstitutivemodelforgradualsofteningbehaviorofjointsofgeomaterials.Correspondingnumericaltestsarecarriedoutatthelocallevel.Characteristicsofthemodelproposedare1)plasticsofteninganddilatancybehavioraredirectlyrelatedtothefractureprocessofjoint,andmuchlessmaterialandmodelparametersarerequiredcomparedwiththoseproposedbyreferences;2)theprocessofdecohesioncoupledwithfrictionalslidingatbothmicro-scaleandmacro-scaleisdescribed.

  • 标签: interface CRACK quasi-brittle FRACTURE joint element
  • 简介:土壤结构接口的行为在土壤结构相互作用的定义起一个主要作用。在这糊双性人潜力表面为土壤结构接口的elasto塑料的模型被建议以便描述接口变丑行为,包括紧张弄软和正常膨胀性。模型在概括潜在的理论,土壤结构接口问题作为压力地里的一个二维的数学问题在是问候的框架被提出,并且塑料州的方程被用来代替传统的域表面。关系曲线砍应力和正切的紧张被明智的功能由夸张功能和夸张正割功能填写了的一片适合,当关系正常弯时,紧张和正切的紧张被明智的功能由二次的功能和夸张正割功能填写了的另一片适合。建议的途径有的优点导出elastoplastic没有要求的组成的矩阵塑料潜在的功能和收益表面。而且,数学原则是清楚的,并且全部模型参数能被试验性的测试识别。最后,模型的预言与获得从的试验性的结果相比简单砍在正常压力下面的测试,和结果证明模型讲理、实际。

  • 标签: 弹塑性本构模型 结构接触面 应变软化 土与结构相互作用 双曲函数 土壤结构
  • 简介:Furthermore,breast-feedingwithoutvitaminDsupplementationcouldprolongthedeficiency,whichmightleadtoariskofserioushealthproblemslaterinlife,includingtype1diabetesanddecreasedbonedensity.'Craniotabes,thesofteningofskullbones,inotherwisenormalnewbornshaslargelybeenregardedasaphysiologicalconditionwithouttheneedfor

  • 标签: 头骨 维生素D 临床分析 健康