学科分类
/ 4
63 个结果
  • 简介:Inthispaper,withPoincare’sformalism,andanindirectmethod,thecanonicalformsofthegeneralizedequationsofmotionduetoNielsenandCenovofaholonomicdynamicalsysteminthevelocity-phasespaceandtheacenleration-phasespaceareobtainedintermsofthePoincareparameters.

  • 标签: HOLONOMIC DYNAMIC SYSTEM Nielsen’s EQUATIONS of
  • 简介:ThesolutionsofGreen'sfunctionaresignificantforsimplificationofproblemonatwo-phasesaturatedmedium.UsingtransformationofaxisymmetriccylindricalcoordinateandSommerfeld'sintegral,superpositionoftheinfluencefieldonafreesurface,authorsobtainedthesolutionsofatwo-phasesaturatedmediumsubjectedtoaconcentratedforceonthesemi-space.

  • 标签:
  • 简介:Thediscretizationsizeislimitedbythesamplingtheorem,andthelimitisonehalfofthewavelengthofthehighestfrequencyoftheproblem.However,onehalfofthewavelengthisanidealvalue.Ingeneral,thediscretizationsizethatcanensuretheaccuracyofthesimulationismuchsmallerthanthisvalueinthetraditionalfiniteelementmethod.Thepossiblereasonofthisphenomenonisanalyzedinthispaper,andanefficientmethodisgiventoimprovethesimulationaccuracy.

  • 标签:
  • 简介:Byusingthefundamentalequationsofaxisymmetricshallowshellsofrevolution,thenonlinearbendingofashallowcorrugatedshellwithtaperunderarbitraryloadhasbeeninvestigated.ThenonlinearboundaryvalueproblemofthecorrugatedshellwasreducedtothenonlinearintegralequationsbyusingthemethodofGreen'sfunction.Tosolvetheintegralequations,expansionmethodwasusedtoobtainGreen'sfunction.ThentheintegralequationswerereducedtotheformwithdegeneratecorebyexpandingGreen'sfunctionasseriesofcharacteristicfunction.Therefore,theintegralequationsbecomenonlinearalgebraicequations.Newton'siterativemethodwasutilizedtosolvethenonlinearalgebraicequations.Toguaranteetheconvergenceoftheiterativemethod,deflectionatcenterwastakenascontrolparameter.Correspondingloadswereobtainedbyincreasingdeflectiononebyone.Asanumericalexample,elasticcharacteristicofshallowcorrugatedshellswithsphericaltaperwasstudied.Calculationresultsshowthatcharacteristicofcorrugatedshellschangesremarkably.Thesnappinginstabilitywhichisanalogoustoshallowsphericalshellsoccurswithincreasingloadifthetaperisrelativelylarge.Thesolutionisclosetotheexperimentalresults.

  • 标签: GREEN函数 非线性弯曲度 边界值 积分方程 弹性系数
  • 简介:Noether’stheoremrevealstheinnerconnectionbetweentheconservationlawsandthedynamicalsymmetryofdynamicalsystems.Intherecenttwent...

  • 标签: analytical MECHANICS UNILATERAL CONSTRAINT conservation law
  • 简介:Liquid-solid(L-S)masstransfercoefficients(Ks)werecharacterizedinagas-liquid-solid(G-L-S)three-phasecountercurrentmagneticallystabilizedbed(MSB)usingamorphousalloySRNA-4asthesolidphase.Effectsofsuperficialliquidvelocity,superficialgasvelocity,magneticfieldstrength,liquidviscosityandsurfacetensionwereinvestigated.ExperimentalresultsindicatedthattheexternalmagneticfieldincreasedKsinthree-phaseMSB,ascomparedtothoseinconventionalG-L-Sfluidizedbeds;thatKsincreasedwithmagneticfieldstrength,superficialgasandliquidvelocitiesanddecreasedwithliquidviscosityandsurfacetension;andthatKsshoweduniformaxialandradialdistributionsexceptforsmallincreasesclosetothewall.DimensionlesscorrelationswereestablishedtoestimateKsoftheG-L-ScountercurrentMSBusingSRNA-4catalyst,withanaverageerrorof3.6%.

  • 标签: 磁力稳定床 对流 液体-固体传质 非晶态合金 SRNA-4催化剂
  • 简介:Thispaperaimstoinvestigatethehydrodynamicbehaviorofatensionlegplatform(TLP)whenthetendonconnectionanglesarevariedat90°,70°,50°,and30°.ThreedifferenttypesofloadingconditionsareappliedtotheTLP.Conditionsinclude100-yearhurricanestormperiod,regularwavesandnoloading.TheTLPdisplayedmajorresponseinthepitchdegreeoffreedom.Amaximumreductionof14%inpitchrotationisachievedwhen100-yearhurricanestormconditionsareappliedtotheTLP.Thisoccurredin0°loadingsat30°tendonconnectionangleascomparedto90°tendonconnectionangle.Reductioninpitchrotationisalsoachievedintheregularwaveloadings.Amaximumof9%inpitchrotationisachievedduring0°waveloadingat30°tendonconnectionangleascomparedto90°.Whenthetendonconnectionangleisreducedfrom90°to30°,thenaturalfrequencyoftheTLPincreasedbothinpitchandyawdegreesoffreedomby2.55%and2.40%,respectively.

  • 标签: TENDON CONNECTION IRREGULAR WAVES Regular WAVES
  • 简介:Astandardconservationformisderivedinthispaper.ThehyperbolicityofHelbing’sfluiddynamictrafficflowmodelisproved,whichisessentialtothegeneralanalyticalandnumericalstudyofthismodel.Onthebasisofthisconservationform,alocaldiscontinuousGalerkinschemeisdesignedtosolvetheresultingsystemefficiently.Theevolutionofanunstableequilibriumtrafficstateleadingtoastablestop-and-gotravelingwaveissimulated.Thissimulationalsoverifiesthatthemodelistrulyimprovedbytheintroductionofthemodifieddiffusioncoefficients,andthushelpstoprotectvehiclesfromcollisionsandavoidetheappearanceoftheextremelylargedensity.

  • 标签: 交通流模型 流体动力学 保护 GALERKIN 模拟验证 数值研究
  • 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:ThispaperisconcernedwiththediffusiveNicholson’sblowfliesequationwithnonlocaldelayincorporatedasanintegralconvolutionovertheentirepasttimeuptonowandthewholeone-dimensionalspatialdomainR.Assumethatthedelaykernelisastronggenerickernel.Bythelinearchaintechniquesandthegeometricsingularperturbationtheory,theexistenceoftravellingfrontsolutionsisshownforsmalldelay.

  • 标签: 延迟积分方程 非局部时滞 苍蝇 扩散 波前解 几何奇异摄动理论
  • 简介:IntroductionWhenanalyzingthedynamicinteractionofasoil_structuresystem,thekeystepistocalculatethedynamicstiffnessmatrixoftheso...

  • 标签: transversely ISOTROPIC LAYERED ELASTIC STRATA Green’s
  • 简介:ThispaperusesPoincaréformalismtoextendtheLevi-Civitatheoremtocopewithnonholonomicsys-temsadmittingcertaininvariantrelationswhoseequationsofmotioninvolveconstraintmultipliers.Sufficientcondi-tionsallowingsuchextensionareobtainedand,asanapplicationofthetheoryageneralizationofRouth’smotionispresented.

  • 标签: NONHOLONOMIC DYNAMICAL systems Levi-Civita’s THEOREM POINCARÉ
  • 简介:The1/3subharmonicsolutionfortheDuffing'sequationisinvestigatedbyusingthemethodsofharmonicbalanceandnumericalintegration.Thesensitivityofparametervariationforthetransientprocessandthetransientprocessfortheperturbanceinitialconditionsarestudied.Overandabove,theprecisionofnumericalintegrationmethodisdiscussedandthenumericalintegrationmethodiscomparedwiththeharmonicbalancemethod.Finally,asymptoticalstabilityofthepuresubharmonicoscillationselementisinspected.

  • 标签: Duffing' s EQUATION SUBHARMONIC TRANSIENT PROCESS
  • 简介:Becausemostpiezoelectricdeviceshaveinterfaceswithfluidinengineering,itisvaluabletostudythecoupledfieldbetweenfluidandpiezoelectricmedia.Asthefundamentalproblem,the3DGreen'sfunctionsforpointforcesandpointchargeloadedinthefluidandpiezoelectricbimaterialsarestudiedinthispaper.Basedonthe3Dgeneralsolutionsexpressedbyharmonicfunctions,weconstructedthesuitableharmonicfunctionswithundeterminedconstantsatfirst.Then,thecouplefieldinthefluidandpiezoelectricbimaterialscanbederivedbysubstitutionofharmonicfunctionsintogeneralsolutions.Theseconstantscanbeobtainedbyvirtueofthecompatibility,boundary,andequilibriumconditions.Atlast,thecharacteristicsoftheelectromechanicalcoupledfieldsareshownbynumericalresults.

  • 标签: 压电材料 流体 格林函数 三维 机电耦合场 GREEN函数
  • 简介:ForthefamousFeigenbaum’sequations,inthispaper,weestablisheditsconstructivetheoremofthepeak-unimodal,thenwefoundoutotherpathstoexplorethepeak-unimodalsolutions.Forexample,weproceedonthedirectiontotrythenon-symmetricalcontinuouspeak-unimodalsolutionsandC~1solutions.

  • 标签: SYMMETRICAL proceed bifurcation CHAOTIC chaos doubling