简介:Theproblemonthedynamicresponseofarigidembeddedfoundationinthepresenceofanundergroundrigidtunnelandsubjectedtoexcitationofincidentanti-planeSHwavesisanalyzed.Byusingtheexactanalyticalsolutionforthetwo-dimensionalSH-wavepropagationinandaroundboththesurfacerigidfoundationandsubsurfacerigidtunnel,thoseaspectsoftheresultinggroundmotionsthatareofspecialinterestandimportanceforseismicresistantdesigninearthquakeanalyseshavebeenexamined.Thecomputedamplitudesoftheresultingperiodicgroundmotionsdisplayaverycomplicatedwave-interferencebetweenthesurfacefoundationandundergroundtunnelthatleadtoobservedstandingwavepatterns,togetherwithabruptchangesinthewaveamplitudesandlargeamplificationoftheincidentmotions.
简介:Forthedynamicsofarigidbodywithafixedpointbasedonthequaternionandthecorrespondinggeneralizedmomenta,adisplacement-basedsymplecticintegrationschemefordifferential-algebraicequationsisproposedandappliedtotheLagrange’sequa-tionsbasedondependentgeneralizedmomenta.Numericalexperimentsshowthatthealgorithmpossessessuchcharactersashighprecisionandpreservingsysteminvariants.Moreimportantly,thegeneralizedmomentabasedLagrange’sequationsshowuniquead-vantagesoverthetraditionalLagrange’sequationsinsymplecticintegrations.
简介:Accordingtothelower-boundtheoremoflimitanalysistheRigidFiniteElementMeth-od(RFEM)isappliedtostructurallimitanalysisandthelinearprogrammingsforlimitanalysisarededucedinthispaper.Moreover,theThermo-ParameterMethod(TPM)andParametricVariationalprinciples(PVP)areusedtoreducethecomputationaleffortwhilemaintainingtheaccuracyofsolutions.Abettersolutionisalsoobtainedinthispaper.
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简介:Inthepresentpaper,afour-stageperforationmodelthataccuratelypredictstheresidualvelocityisdevelopedbyadoptinganenergymethod.Thefourstagesareplugformation,dishingformation,petalformationandprojectileexit.Inaddition,someimportantexperimentalresultsarepresentedandanalyzedtovalidatethepresentperforationmodel.Intheexperiments,highspeedcamerasystemisusedtorecordtheperforationprocess.Observationsontargetdamageandmeasurementsofinitialvelocitiesandresidualvelocitieswiththeaidofthesystemarepresented.Numericalsimulationsarecarriedoutforprojectilesagainstsingleandlayeredplatesadoptedintheexperiments.Theperforationprocessisstudiedandthedeformationandfailuremodesareobtained.Thepredictionsofnumericalsimulationsandanalyticalmodelarefoundinreasonablygoodagreementwiththoseofexperiments,andcanbeusedtopredicttheballisticlimitandresidualvelocityofstiffenedplatesperforatedbyrigidprojectiles.
简介:LetM(2)bethegroupofrigidmotionsoftheplane.TheFouriertransformandthePiancherelformulaonM(2)canbeexplicitlygivenbythegeneralgrouprepresentationtheory.Usingthisfact.weestablishakindofuncertaintyprincipleonM(2).Theresultcaneasilybegeneralizedtohigherdimensionalcases.AnapplicationoftheresultyieldsanuncertaintyprincipleontheEuclideanspacesobtainedbyR.S.Strichartz.
简介:RigidFiniteElementMethod(RFEM)wasproposedtosimulatethemechanicalbehaviorofdiscontinuousstructuressuchasrockandsoilstructures.Theauthors’workonthetheoryandapplicationsofRFEMissummarizedinthispaper.BasedonthetheoryofRFEM,theElasticBody-SeamsModel(EBSM)isproposedtotakethedeformationanddamageofrockmassesintoaccount.
简介:Basedonanincompressiblemodel,byusingthelargestaintheory,thecontactofarubberwedgewitharigidnotchisanalyzedbytheasymptoticmethod.Theproblemistreatedasasymmetriccase,andthecontactsurfaceissmooth.Thestressandstrainfieldneartheapexoftherubberwedgeisshowntobesingular,andtheangulardistributionsofstressandstrainareobtained.Twoimportantparameterstandtareintroducedtoattaintheconclusions.TheresultshowsthatthesingularexponentorderofstressfieldisInr.
简介:Asimplifiedfatigue-lifemodelisproposedforassessingtheseismicinelasticrotationalcapacityofsteelconnections.Firstrelationsaredevelopedforrigidsteelconnectionsunderlateralloading.Nextthisisextendedtoaccountfortheeffectsoftheweldedsteelmomentframe(WSMF)connectionsoftheso-calledpre-Northridgetype.Theseismicfatiguetheoryisvalidatedagainstexperimentalresults.Theexperimentswereconductedunderincreasingductilityamplitudcsuntiltheonsetoffracture.Miner'rulewasusedtoconvertthetestresultstogivenanequivalentconstantamplitudecyclicfatiguelife.Satisfactoryagreementisobtainedwhencomparingtheexperimentalobservationswiththetheoreticalpredictions.
简介:Hamiltonianstructureofarigidbodyinacircularorbitisestablishedinthispaper.Withthereductiontechnique,theHamiltonianstructureofarigidbodyinacircularorbitisderivedfromLie-Poissonstructureofsemidirectproduct,andHamiltonianisderivedfromJacobi’sintegral.TheabovemethodcanbegeneralizedtoestablishtheHamiltonianstructureofarigidbodywithaflexibleattachmentinacircularor-bit.Atlast,anexampleofstabilityanalysisisgiven.
简介:Anewmethodformeasuring3-Drigidbodydisplacementsisproposed,inwhichtwoperpendicularbeamsareemittedontotwosensitiveplanesofPSDsleingperpendiculartoeachother.Themethodcanbeusedtomeasure1-Dor2-Ddisplacementswhenrequired.Moreover,theexperimentalresultsarepresented,whichdemonstratethatthenewmethodhashighaccuracy,fastprocessingspeed,highreliability,andeasilybeingrealized.
简介:DoubleBeamstoMeasureThree-dimensionalRigidBodyDisplacements①ZHOUJian,CHENWenyi,ZHAOHongTIANFeng,TANYushan(ResearchInstitutefo...
简介:Thefinitetimetrackingproblemisconsideredforroboticmanipulatorswithunknowndynamicfriction,boundeddisturbancesandunmodeleddynamics.Aglobalrelayswitchingcontrolschemewithfinitetimeconvergenceisproposed.Forgeneralfinitetimevariablestructurecontroller,thecontrolsignalsmayescapetoinfiniteinfinitetimewhentheinitialstatesofthesystemareinsomespecifiedarea,causingthesingularityphenomenaoftheclosed-loopsystem.Thedesignschemeforfinitetimetrackingcontrolusesatwo-phaseswitchingcontrolmethodsothattheboundednessofthecontrolsignalisguaranteedandthesingularityphenomenaisavoided.
简介:Anumericalmethodforsimulatingnonlinearfluid-rigidstructureinteractionproblemsisdeveloped.Thestructureisassumedtoundergolargerigidbodymotionsandthefluidflowisgovernedbynonlinear,viscousornon-viscous,fieldequationswithnonlinearboundaryconditionsappliedtothefreesurfaceandfluid-solidinteractioninterfaces.AnArbitrary-Lagrangian-Eulerian(ALE)meshsystemisusedtoconstructthenumericalmodel.Amulti-blocknumericalschemeofstudyisadoptedallowingfortherelativemotionbetweenmovingoversetgrids,whichareindependentofoneanother.Thisprovidesaconvenientmethodtoovercomethedifficultiesinmatchingfluidmesheswithlargesolidmotions.Nonlinearnumericalequationsdescribingnonlinearfluid-solidinteractiondynamicsarederivedthroughanumericaldiscretizationschemeofstudy.Acouplingiterationprocessisusedtosolvethesenumericalequations.Numericalexamplesarepresentedtodemonstrateapplicationsofthemodeldeveloped.
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.
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.
简介:OnthebasisofHamilton’sprincipleanddynamicversionofvonKàrmàn’sequations,thenonlinearvibrationandthermal-bucklingofauniformlyheatedisotropicannularplatewithacompletelyclampedouteredgeandafixedrigidmassalongtheinneredgearestudied.Byparametricperturbationandnumericaldifferentiation,thenonlinearresponseoftheplate-masssystemandthecriticaltemperatureinthemid-planeatwhichtheplateisinbuckledstateareobtained.Somemeaningfulcharacteristiccurvesanddatatablesaregiven.