学科分类
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13 个结果
  • 简介:Anappropriatecoupledcohesivelawforpredictingthemixedmodefailureisestablishedbycombiningnormalseparationandtangentialseparationofsurfacesinthecohesivezonemodel(CZM)andthecohesiveelementmethod.TheXu-Needlemanexponentialcohesivelawwiththefullyshearfailuremechanismisoneofthemostpopularmodels.Basedontheproposedconsistentlycoupledrule/principle,theXu-Needlemanlawwiththefullyshearfailuremechanismisprovedtobeanon-consistentlycoupledcohesivelawbyanalyzingthesurfaceseparationwork.ItisshownthattheXu-Needlemanlawisonlyvalidinthemixedmodefracturewhenthenormalseparationworkequalsthetangentialseparationwork.BasedontheconsistentlycoupledprincipleandthemodificationoftheXu-Needlemanlaw,aconsistentlycoupledcohesive(CCC)lawisgiven.ItisshownthattheproposedCCClawhasalreadyovercomethenon-consistencydefectoftheXu-Needlemanlawwithgreatpromiseinmixedmodeanalyses.

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  • 简介:Animprovedconstrained(IC)steeringlawforsinglegimbalcontrolmomentgyros(SGCMGs)withdeformedpyramidconfiguration(DPC)isproposed.Firstofall,theoriginalsystemwithfivepyramidconfiguration(FPC)whosetwoadjacentgyrosareinfailurestateisreconfiguredasadegradedsystemwithDPC.Then,thesingularangularmomentumhypersurfacesoftheoriginalandthedegradedsystemsareplottedviathesingularangularmomentumequationofSGCMGs.Basedonsingularsurfaces,thedifferencesbetweenFPCandDPCinsingularityandmomentumenvelopeareobtaineddirectly,whichprovideanimportantreferenceforsteeringlawdesignofDPC.Finally,anICsteeringlawisdesignedandappliedtoDPC.ThesimulationresultsdemonstratethattheICsteeringlawhasadvantagesinsimplicityofcalculation,avoidanceofsingularityandexactnessofoutputtorque,whichendowthedegradedsystemwithfinecontrollabilityinarestrictedworkspace.

  • 标签: 转向系统 DPC 法律 单框架控制力矩陀螺 集成电路 结构变形
  • 简介:Weprovideanalyticalsolutionstotheproblemsofacircularbendingofabeaminplanestrainandthetorsionofanon-circularcross-sectionbeam,thebeamsobeyingasecond-gradientelasticitylawproposedbytheauthor,followingaprevioussuggestionofdell'Isolaetal.(2009).Themotivationwastofindbenchmarkanalyticalsolutionsthatcanservetograspthephysicalfoundationsofsecondgradientelasticitylawsforheterogeneousmaterials.TheanalyticalsolutionofthecircularbeamproblempresentstheadditionaladvantagetoestablishsomenicepropertiesontheunknownsecondgradientelasticmoduliintroducedbyEnakoutsa(2014)modelandtheclassicalelasticityconstantsforbothincompressibleandcompressibleheterogeneouselasticmaterials.Aframeworktofindtheelasticmoduliofthenewmodelisalsoproposed.

  • 标签: 梯度材料 广义虎克定律 应用 弹性定律 材料弹性常数 弹性模量
  • 简介:Researchonparticulatecharacteristicshasbeenanimportantfrontierinphysicsandchemistryduringthepastdecades.Ithashoweverbeenmostlyfocusedongranularmaterialswithshort-rangeinteractions.Inthiswork,itwasfoundthatthepowerlawofparticlesizedistributionappliedtothelong-rangeinteractingsystemoffloatingdustinair,fromwhichwededucedthatself-organizedcriticalitymightholdforfloatingdustjustasgranularmaterialswithshort-rangeinteractions.Thisfeaturemayrevealunderlyingkineticmechanisms,importantindispersedparticlesystems.Inindustry,powerlawofsizedistributionofdispersedparticlescanbeusedtoinvestigatethechangeofdustsize,andthepowerlawparametercouldbetakenasanimportantindexfordustseparation.

  • 标签: 能量分布定律 散布粒子 悬浮尘埃 危险程度
  • 简介:一个新方法被开发因为在在同一直线上的振动点上稳定运动用限制的通报的形式主义绕三个身体问题转。关于在同一直线上的振动点轨道的Linearization与周期的系数产出一个不稳定的线性变化参数的系统。给变化方程,一条创新控制法律为振动点轨道基于典型代表赋值被介绍维护。选择理查森鈥檚的数字模拟为一条名字的轨道被进行的一条光圈轨道的第三顺序近似,和结果表明这条控制法律的有效性。关键词通报限制了三个身体问题-变化方程-振动点轨道维护-典型代表赋值工程被中国(10702003)的国家自然科学基础支持。

  • 标签: 轨道维持 特征指数 线性振动 基础 配置 控制点
  • 简介:ThroughacomparisonbetweentheexpressionsofmasterbalancelawsandtheconservationlawsderivedbyNoether'stheorem,aunifiedmasterbalancelawandsixphysicallypossiblebalanceequationsformicropolarcontinuummechanicsarenaturallydeduced.Amongthem,byextendingthewell-knownconventionalconceptofenergymomentumtensor,therathergeneralconservationlawsandbalanceequationsnamedafterenergy-momentum,energy-angularmomentumandenergy-energyareobtained.Itisclearthattheformsofthephysicalfieldquantitiesinthemasterbalancelawforthelastthreecasescouldnotbeassumeddirectlybyperceivingthroughtheintuition.Finally,someexistingresultsarereducedimmediatelyasspecialcases.

  • 标签: 极性连续理论 平衡控制法则 物理量域 守恒理论 能量 动量
  • 简介:InteractionbetweentwosphereswithaninterstitialfluidisessentialinDiscreteElementmodelingforsimulatingthebehaviorsof'wet'particulatematerials.InthispapertheinteractionbetweentwosphereswithaninterstitialPower-lawfluidwasapproximatelyresolvedasnormalandtangentialinteractivemodelsrespectively,forwhichthegoverningequationsweresimplifiedonthebasisofReynoldsapproximation.Theseequationswerethensolvedanalyticallytogetherwiththeboundaryconditionstoobtainthepressuredistributionsforeachindividualmodel,andeventuallysolutionsoftheviscoussqueezeforceandthetangentialviscousresistancewereobtained,whichprovideasetofsolutionsforimplementingintoDEMcodeorotherpurposes.

  • 标签: 潮湿粒子 离散元法 幂律流体 粘着力
  • 简介:Thesteadytwo-dimensionalmagnetohydrodynamicstagnationflowtowardsanonlinearstretchingsurfaceisstudied.Theno-slipconditiononthesolidboundaryisreplacedwithapartialslipcondition.Ascalinggrouptransformationisusedtogettheinvariants.Usingtheinvariants,athird-orderordinarydifferentialequationcorrespondingtothemomentumisobtained.Ananalyticalsolutionisobtainedinaseriesformusingahomotopyanalysismethod.Reliabilityandefficiencyofseriessolutionsareshownbythegoodagreementwithnumericalresultspresentedintheliterature.Theeffectsoftheslipparameter,themagneticfieldparameter,thevelocityratioparameter,thesuctionvelocityparameter,andthepowerlawexponentontheflowareinvestigated.Theresultsshowthatthevelocityandshearstressprofilesaregreatlyinfluencedbytheseparameters.

  • 标签: 血液透析 三阶常微分方程 流量 伸展 权力 滞点
  • 简介:InthisworkweproposetoreplacetheGLPDhypo-elasticitylawbyamorerigorousgeneralizedHooke’slawbasedonclassicalmaterialsymmetrycharacterizationassumptions.ThislawintroducesinadditiontothetwowellknownLame’smoduli,fiveconstitutiveconstants.AnanalyticalsolutionisderivedfortheproblemofasphericalshellsubjectedtoaxisymmetricloadingconditionstoillustratethepotentialoftheproposedgeneralizedHooke’slaw.

  • 标签: 轴对称载荷 弹性定律 本构关系 广义 载荷条件 材料
  • 简介:电影动量和在加速上的薄有限幂定律液体的热运输特征上的内部加热来源的效果不稳定的水平拉长的接口被学习。不同于这块地里的很古典的工作,为改变热电导率的液体电影和概括Fouriers法律的一般表面温度分布被考虑。适当类似转变被用来与一组二点的平常的微分方程(颂诗)把强烈非线性的管理部分微分方程(PDE)变换成一个边界价值问题。在液体电影厚度和摇摆参数之间的通讯在MATLAB用BVP4C节目被导出。自我类似颂诗的数字答案用与一个Runge-Kutta重复程序和牛顿计划相结合的射击技术被获得。液体上的深奥物理参数的效果水平速度和温度分发被介绍并且讨论。

  • 标签: 非牛顿的液体 非线性的方程 薄电影 加热转移 内部加热 拉长表
  • 简介:Inthepresentpaper,thecompatibilityequationfortheplanestressproblemsofpower-lawmaterialsistransformedintoabiharmonicequationbyintroducingtheso-calledcomplexpseudo-stressfunction,whichmakesitpossibletosolvetheelastic-plasticplanestressproblemsofstrainhardeningmaterialsdescribedbypower-lawusingthecomplexvariablefunctionmethodlikethatinthelinearelasticitytheory.Byusingthisgeneralmethod,theclose-formedanalyticalsolutionsforthestress,strainanddisplacementcomponentsoftheplanestressproblems’ofpower-lawmaterialsisdeducedinthepaper,whichcanalsobeusedtosolvetheelasto-plasticplanestressproblemsofstrain-hardeningmaterialsotherthanthatdescribedbypower-law.Asanexample,theproblemofapower-lawmaterialinfiniteplatecontainingacircularholeunderuniaxialtensionissolvedbyusingthismethod,theresultsofwhicharecomparedwiththoseofaknownasymptoticanalyticalsolutionobtainedbytheperturbationmethod.

  • 标签: POWER-LAW MATERIALS pseudo-stress FUNCTION plane STRESS