学科分类
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36 个结果
  • 简介:Theproblemonthedynamicresponseofarigidembeddedfoundationinthepresenceofanundergroundrigidtunnelandsubjectedtoexcitationofincidentanti-planeSHwavesisanalyzed.Byusingtheexactanalyticalsolutionforthetwo-dimensionalSH-wavepropagationinandaroundboththesurfacerigidfoundationandsubsurfacerigidtunnel,thoseaspectsoftheresultinggroundmotionsthatareofspecialinterestandimportanceforseismicresistantdesigninearthquakeanalyseshavebeenexamined.Thecomputedamplitudesoftheresultingperiodicgroundmotionsdisplayaverycomplicatedwave-interferencebetweenthesurfacefoundationandundergroundtunnelthatleadtoobservedstandingwavepatterns,togetherwithabruptchangesinthewaveamplitudesandlargeamplificationoftheincidentmotions.

  • 标签: SH WAVES wave-interference embedded FOUNDATION UNDERGROUND
  • 简介:Forthedynamicsofarigidbodywithafixedpointbasedonthequaternionandthecorrespondinggeneralizedmomenta,adisplacement-basedsymplecticintegrationschemefordifferential-algebraicequationsisproposedandappliedtotheLagrange’sequa-tionsbasedondependentgeneralizedmomenta.Numericalexperimentsshowthatthealgorithmpossessessuchcharactersashighprecisionandpreservingsysteminvariants.Moreimportantly,thegeneralizedmomentabasedLagrange’sequationsshowuniquead-vantagesoverthetraditionalLagrange’sequationsinsymplecticintegrations.

  • 标签: 偶对的法则 刚性力学 四元数 动力学
  • 简介:Accordingtothelower-boundtheoremoflimitanalysistheRigidFiniteElementMeth-od(RFEM)isappliedtostructurallimitanalysisandthelinearprogrammingsforlimitanalysisarededucedinthispaper.Moreover,theThermo-ParameterMethod(TPM)andParametricVariationalprinciples(PVP)areusedtoreducethecomputationaleffortwhilemaintainingtheaccuracyofsolutions.Abettersolutionisalsoobtainedinthispaper.

  • 标签: RIGID finite element METHOD Limit analysis
  • 简介:Inthepresentpaper,afour-stageperforationmodelthataccuratelypredictstheresidualvelocityisdevelopedbyadoptinganenergymethod.Thefourstagesareplugformation,dishingformation,petalformationandprojectileexit.Inaddition,someimportantexperimentalresultsarepresentedandanalyzedtovalidatethepresentperforationmodel.Intheexperiments,highspeedcamerasystemisusedtorecordtheperforationprocess.Observationsontargetdamageandmeasurementsofinitialvelocitiesandresidualvelocitieswiththeaidofthesystemarepresented.Numericalsimulationsarecarriedoutforprojectilesagainstsingleandlayeredplatesadoptedintheexperiments.Theperforationprocessisstudiedandthedeformationandfailuremodesareobtained.Thepredictionsofnumericalsimulationsandanalyticalmodelarefoundinreasonablygoodagreementwiththoseofexperiments,andcanbeusedtopredicttheballisticlimitandresidualvelocityofstiffenedplatesperforatedbyrigidprojectiles.

  • 标签: 刚性发射 穿孔 碰撞 硬质板 数字模拟 故障模式
  • 简介:LetM(2)bethegroupofrigidmotionsoftheplane.TheFouriertransformandthePiancherelformulaonM(2)canbeexplicitlygivenbythegeneralgrouprepresentationtheory.Usingthisfact.weestablishakindofuncertaintyprincipleonM(2).Theresultcaneasilybegeneralizedtohigherdimensionalcases.AnapplicationoftheresultyieldsanuncertaintyprincipleontheEuclideanspacesobtainedbyR.S.Strichartz.

  • 标签: uncertainty Euclidean NEIGHBORHOOD rigid normalized explicitly
  • 简介:RigidFiniteElementMethod(RFEM)wasproposedtosimulatethemechanicalbehaviorofdiscontinuousstructuressuchasrockandsoilstructures.Theauthors’workonthetheoryandapplicationsofRFEMissummarizedinthispaper.BasedonthetheoryofRFEM,theElasticBody-SeamsModel(EBSM)isproposedtotakethedeformationanddamageofrockmassesintoaccount.

  • 标签: rock and soil ENGINEERING RIGID FINITE
  • 简介:Basedonanincompressiblemodel,byusingthelargestaintheory,thecontactofarubberwedgewitharigidnotchisanalyzedbytheasymptoticmethod.Theproblemistreatedasasymmetriccase,andthecontactsurfaceissmooth.Thestressandstrainfieldneartheapexoftherubberwedgeisshowntobesingular,andtheangulardistributionsofstressandstrainareobtained.Twoimportantparameterstandtareintroducedtoattaintheconclusions.TheresultshowsthatthesingularexponentorderofstressfieldisInr.

  • 标签: 不可压缩模型 橡胶楔 渐近线理论 刚性槽口 应变场 固体力学
  • 简介:Asimplifiedfatigue-lifemodelisproposedforassessingtheseismicinelasticrotationalcapacityofsteelconnections.Firstrelationsaredevelopedforrigidsteelconnectionsunderlateralloading.Nextthisisextendedtoaccountfortheeffectsoftheweldedsteelmomentframe(WSMF)connectionsoftheso-calledpre-Northridgetype.Theseismicfatiguetheoryisvalidatedagainstexperimentalresults.Theexperimentswereconductedunderincreasingductilityamplitudcsuntiltheonsetoffracture.Miner'rulewasusedtoconvertthetestresultstogivenanequivalentconstantamplitudecyclicfatiguelife.Satisfactoryagreementisobtainedwhencomparingtheexperimentalobservationswiththetheoreticalpredictions.

  • 标签: FATIGUE CYCLIC load SEISMIC pile-to-cap MOMENT
  • 简介:Hamiltonianstructureofarigidbodyinacircularorbitisestablishedinthispaper.Withthereductiontechnique,theHamiltonianstructureofarigidbodyinacircularorbitisderivedfromLie-Poissonstructureofsemidirectproduct,andHamiltonianisderivedfromJacobi’sintegral.TheabovemethodcanbegeneralizedtoestablishtheHamiltonianstructureofarigidbodywithaflexibleattachmentinacircularor-bit.Atlast,anexampleofstabilityanalysisisgiven.

  • 标签: HAMILTONIAN structure POISSON MANIFOLD rigid-elastic COUPLED
  • 简介:Anewmethodformeasuring3-Drigidbodydisplacementsisproposed,inwhichtwoperpendicularbeamsareemittedontotwosensitiveplanesofPSDsleingperpendiculartoeachother.Themethodcanbeusedtomeasure1-Dor2-Ddisplacementswhenrequired.Moreover,theexperimentalresultsarepresented,whichdemonstratethatthenewmethodhashighaccuracy,fastprocessingspeed,highreliability,andeasilybeingrealized.

  • 标签: 显示测量 三维物体 光感测器
  • 简介:DoubleBeamstoMeasureThree-dimensionalRigidBodyDisplacements①ZHOUJian,CHENWenyi,ZHAOHongTIANFeng,TANYushan(ResearchInstitutefo...

  • 标签: Displacements Measurement PHOTODETECTOR PSD
  • 简介:Thefinitetimetrackingproblemisconsideredforroboticmanipulatorswithunknowndynamicfriction,boundeddisturbancesandunmodeleddynamics.Aglobalrelayswitchingcontrolschemewithfinitetimeconvergenceisproposed.Forgeneralfinitetimevariablestructurecontroller,thecontrolsignalsmayescapetoinfiniteinfinitetimewhentheinitialstatesofthesystemareinsomespecifiedarea,causingthesingularityphenomenaoftheclosed-loopsystem.Thedesignschemeforfinitetimetrackingcontrolusesatwo-phaseswitchingcontrolmethodsothattheboundednessofthecontrolsignalisguaranteedandthesingularityphenomenaisavoided.

  • 标签: 有限时间跟踪控制系统 机器人 操作系统 摩擦力 转换控制法
  • 简介:Anumericalmethodforsimulatingnonlinearfluid-rigidstructureinteractionproblemsisdeveloped.Thestructureisassumedtoundergolargerigidbodymotionsandthefluidflowisgovernedbynonlinear,viscousornon-viscous,fieldequationswithnonlinearboundaryconditionsappliedtothefreesurfaceandfluid-solidinteractioninterfaces.AnArbitrary-Lagrangian-Eulerian(ALE)meshsystemisusedtoconstructthenumericalmodel.Amulti-blocknumericalschemeofstudyisadoptedallowingfortherelativemotionbetweenmovingoversetgrids,whichareindependentofoneanother.Thisprovidesaconvenientmethodtoovercomethedifficultiesinmatchingfluidmesheswithlargesolidmotions.Nonlinearnumericalequationsdescribingnonlinearfluid-solidinteractiondynamicsarederivedthroughanumericaldiscretizationschemeofstudy.Acouplingiterationprocessisusedtosolvethesenumericalequations.Numericalexamplesarepresentedtodemonstrateapplicationsofthemodeldeveloped.

  • 标签: 流体结构作用 非线性数字仿真 ALE 点阵翻转 物理耦合 有限元
  • 简介:Objective:Tointroducethetechniqueofsubciliaryincisionandlateralcantholysiswithtri-dimensionreductionandrigidinternalfixationtotreatzygomaticcomplexfractures.Methods:Thesubciliaryincisionandlateralcantholysiscombinedwithtri-dimensionreductionandrigidinternalfixationofzygomaticcomplexfractureswithtitaniummicroplateswereappliedin56patientswithzygomaticcomplexfractures.Anotherlateraleyebrowincisionorsublabialincisionwasusedtosimplifytheoperation.Results:Thepostoperativefollow-upperiodrangedfrom6monthsto5years.Duringthefollow-upperiod,allthepatientshadsatisfyingpostoperativeresults.Allclinicalsymptomsdisappearedexceptthenumbnessintheinfraorbitalregionin2patients.In94.6%patientsnocomplicationssuchasobviousscar,ectropion,entropionorblepharoedemawerefound,only5.4%ofthepatientshadslightectropion6monthsafteroperation.Conclusions:Thesubciliaryincisionandlateralcantholysishavemanyadvantagessuchasinvisiblescar,sufficientexposure,minimalinjury,andfewcomplicationsandcombinedwithrigidinternalfixationwithtitaniummicroplatesthistechniquecouldbeusedasoneoftheroutineoperationmethodstotreatzygomaticcomplexfractures.

  • 标签: 颧骨复杂性骨折 内固定 手术治疗 手术入路 创伤
  • 简介:Heptacyclo[6.6.0.02,6.03,13.04,11.05,9,010,14]tetradecaneisacage-shapedmoleculeofbothhighsymmetry(D2d)andhighrigidity.Inourpreviousreports,ithasbeenusedasanuniquespacergroupforelectrontransferprocessesbetweenadonor(D)andanacceptor(A)substituent.TheDandAchromophorescanbealignedalongastraightline,eithercoplanar(0°dihedralangle)orperpendicular(90°dihedralangle)withrespecttoeachother.Knowledgecollectedinthisworkmaybeusefulforthedesignofphoto-electronicdevices,suchaselectrochemicalsensors,photovoltaiccells,molecularrectifiersandswitches,etc.

  • 标签:
  • 简介:OnthebasisofHamilton’sprincipleanddynamicversionofvonKàrmàn’sequations,thenonlinearvibrationandthermal-bucklingofauniformlyheatedisotropicannularplatewithacompletelyclampedouteredgeandafixedrigidmassalongtheinneredgearestudied.Byparametricperturbationandnumericaldifferentiation,thenonlinearresponseoftheplate-masssystemandthecriticaltemperatureinthemid-planeatwhichtheplateisinbuckledstateareobtained.Somemeaningfulcharacteristiccurvesanddatatablesaregiven.

  • 标签: plate-rigid MASS system nonlinear vibration thermal-buckling
  • 简介:TheRigidbodyofPaleo-continentinthecrustofTaiwanandtherecentplatemovementGang-XiaLIU(刘光夏),Wen-JunZHAO(赵文俊)Wen-JuREN(任文菊)andXiu...

  • 标签: CRUST of TAIWAN PLATE MOVEMENT