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  • 简介:Basedonthetheoryofelasticdynamics,thescatteringofelasticwavesanddynamicstressconcentrationinfiber-reinforcedcompositewithinterfacesarestudied.Analyticalexpressionsofelasticwavesindifferentmediumareasarepresentedandananalyticmethodofsolvingthisproblemisestablished.Themodecoefficientsaredeterminedbymeansofthecontinuousconditionsofdisplacementandstressontheboundaryoftheinterfaces.Theinfluenceofmaterialpropertiesandstructuralsizeonthedynamicstresscon-centrationfactorsneartheinterfacesisanalyzed.Itindicatesthattheyhaveagreatinfluenceonthedynamicpropertiesoffiber-reinforcedcomposite.Asexamples,numericalresultsofdynamicstressconcentrationfac-torsneartheinterfacesarepresentedanddiscussed.Thispaperprovidesreliabletheoreticalevidenceforthestudyofdynamicpropertiesinfiber-reinforcedcomposite.

  • 标签:fiber-reinforcedcompositeINTERFACESSCATTERINGofELASTIC
  • 简介:有弹性的阻抗(EI)倒置广泛地在工业被使用了估计有点有弹性的参数区分岩性学或甚至液体。然而,常规三术语的有弹性的阻抗公式甚至与在地震数据的细微随机的噪音是不稳定的,这被发现,由于有弹性的参数的性恶的系数矩阵。我们介绍了二术语的Fatti有弹性的阻抗倒置方法,它比常规三术语的有弹性的阻抗倒置更柔韧、精确。在我们的方法,密度被忽略增加倒置矩阵的坚韧性。而且,P阻抗和S阻抗,对随机的噪音不太敏感,被转换而不是VP和V在常规三术语的有弹性的阻抗的S。使倒置更稳定,我们把K价值的范围定义为限制。这个方法能获得答应的合成测试主张与低SNR(信号噪音比率)结果地震数据。用在一个2D线数据的方法的申请,我们完成了,并且VP/VS节,完美地匹配钻的井,在水库预言显示方法的潜力。

  • 标签:反演方法弹性阻抗弹性参数估计随机噪声地震数据
  • 简介:Metamaterialsareartificialcompositematerialsengineeredtohavepropertiesthatmaynotbefoundinnature.Byexploringlocallyresonanteffectofthebuildingunits,elasticmetamaterialsareabletopossessnegativevaluesofeffectivemass,effectivebulkorshearmodulus.Mass-springandcontinuummaterialversionsoftheseelasticmetamaterialsarereportedandthephysicalmechanismsofnegativeeffectiveparametersaredemonstrated.Applicationsofmetamaterialstoacousticcloakingandsuperlensingarealsodiscussed.

  • 标签:复合材料局部振动弹性有效质量共振效应建设单位
  • 简介:Ifthefrequencyoftheincidentsoundwavecoincideswithoneoftheeigenfrequenciesoftheunderwaterelasticcylinder,thecorre-spondingeigenvibrationwillbeexcitedbyincidentsoundwaveandstronglyreradiatesoundwavetowardssurrondingwater.Ithasbeenre-vealedbypreviousinvestigationsthattheamplitudeofbackscatteringsoundappearstobeminimumattheeigenfrequenciesoftheunderwatermetalliccylindersbecauseofthedestructiveinterferencebetweenreradiatedwaveoftheeigenvibrationandthegeometricalreflectedwavefromsurfaceofthecylinders.Inthispaper,anewphenomenonhasbeenrevealed.Theamplitudeofbackscatteringsoundappearstobemaximumattheeigenfrequenciesofacylindermadefromnonmetallicmaterialinwhichthevelocityofelastictransversewaveislessthanthesoundvelocityinwater.

  • 标签:cylindersUNDERWATERexciteddestructiveradiusSUPERPOSITION
  • 简介:Thedynamicresponseofthenon-linearelasticsimplysupportedbeamsubjectedtoaxialforcesandtransverseperiodicloadisstudied.Melnikovmethodisusedtoconsiderthedynamicbehav-iorofthesystemwhosepost-bucklingpathissteady.Theeffectofthehigherordertermsinthecon-trollingequationistakenintoaccount.Itisfoundthatthefifth-ordertermshaveagreatinfluenceonthedynamicbehaviorofthesystem.Theresultshowsthatthereexisteitherhomoclinicorbitsorhete-roclinicorbitsinthesystem.Inthispaper,thecriticalvaluesofthesystementeringchaoticstatesaregiven.Thediagramofanexampleisshown.

  • 标签:CHAOSHOMOCLINICORBITHETEROCLINICORBITMELNIKOV
  • 简介:我们在某些合理假设下面考虑有弹性的薄盘子的颤动。我们由哈密尔顿原则为这个模型导出非线性的方程。在为起始的数据的hyperbolicity上的条件下面,我们建立本地时间well-posedness为起始并且由Picard重复的边界值问题为解决方案策划,并且获得估计。

  • 标签:弹性薄板板振动非线性分析HAMILTON原理非线性方程组初边值问题
  • 简介:ANALYSISOFSTABILITYONELASTICPLATESWITHINITIALIMPERFECTIONSXuKaiyu(徐凯宇)(ReceivedOct.5.1994;CommunicatedPaiLizhou)ANALYSISOFSTA...

  • 标签:imperfection.UNIVERSALunfolding.eigenvalue.BIFURCATION
  • 简介:Withthehelpofthedeclinemethod,acomputer-aidedanalysisprogramofChristoffelequationisdes-cribedwhichmakesitpossibletocalculateelasticandviscousconstantsofcrystalspreciselyandeasily.TheelasticconstantsofLiNbO3andBi12GeO20crystalsarecalculatedwithanApple-ⅡcomputerandtheFortranprogramsuggested,andthecalculateddataarecomparedwiththevaluesachievedbyothers.

  • 标签:CONSTANTSDECLINEAppleultrasonicVISCOUSaided
  • 简介:Thispapergivesallthetwo-dimensionalmembranemodelsobtainedfromformalasymptoticanalysisofthethree-dimensionalgeometricallyexactnonlinearmodelofathinelasticshellmadewithaSaintVenant-Kirchhoffmaterial.Therefore,theothermodelscanbequotedasflexuralnonlinearones.Theauthoralsogivestheformalequationssolvedbytheassociatedstresstensorandpointsoutthatonlyoneofthosemodelsleads,bylinearization,tothe“classical”linearlimitingmembranemodel,whosejuetificationhasalreadybeenestablishedbyaconvergencetheorem.

  • 标签:非线性弹性壳体渐近分析收敛定理利普希茨边界
  • 简介:WeproposeanapplicationoftheelasticneuralnetforringrecognitioninRICHdetectors.Themethodhasbeendevelopedtofindringsdistortedduetomisalignmentofdetectorsandcontaminatedbynoise.ThealgorithmwastestedonsimulateddataofCOMPASSRICH-1detector.Reconstructionefficiencyis99.95%fortripleLEPTOeventstaking5msperevent.

  • 标签:神经网络环形识别方法RICH
  • 简介:Thetransformationmethodtocontrolwaveshasreceivedwidespreadattentioninelectromagnetismandacoustics.However,thismachineryisnotdirectlyapplicabletothecontrolofelasticwaves,becauseithasbeenshownthattheNavier’sequationdoesnotusuallyretainitsformundercoordinatetransformation.Inthisletter,weprovetheforminvarianceoftheNavier’sequationundertheconformalmappingbasedontheHelmholtzdecompositionmethod.Theneededmaterialparametersareprovidedtomanipulateelasticwaves.Thevalidityofthisapproachisconfirmedbyanactivestealthdevicewhichcandisguisethesignalsourcebychangingitsposition.Experimentalverificationsandpotentialapplicationsmaybeexpectedinnondestructivetesting,structuralseismicdesignandotherfields.

  • 标签:声学控制保角映射弹性波Navier方程波形结构抗震设计
  • 简介:Wereportphotoelectronenergyspectraandangulardistributionsforionizationwithelasticscatteringinultrastronglaserfields.NoblegasspecieswithHartree–FockscatteringpotentialsshowareductioninelasticrescatteringwiththeincreasingenergyofultrastrongfieldsandwhentheLorentzdeflectionofthephotoelectronexceedsitswavefunctionspread.Therelativisticextensionofathree-steprecollisionmodeliswell-suitedtotheultrastrongintensityregime(>1017W∕cm2)thatliesbetweentraditionalstrongfieldsandextremerelativisticinteractions.

  • 标签:极端相对论弹性散射散射光电子分布HARTREE-FOCK超强激光场
  • 简介:Afinitedifference/boundaryintegralproceduretodeterminetheacousticreflectedpressurefromafluid-loadedbi-laminatedplateisdescribed.Thebi-laminateiscomposedofapiezoelectriclayerandanelasticlayerincontactwiththefluid,andisheldbyanacousticallyhardbaffle.Inthenumericalmodel,thefluidpressureatfluid/solidinterfaceisreplacedbyacontinuumofpointsourcesweightedbythenormalaccelerationoftheelasticplate,andthegoverningequationsystemissolvedinthesoliddomain.Withthenormalaccelerationfound,thereflectedpressureinthefluidisdeterminedbyanintegralexpressioninvolv-ingtheGreen’sfunction.Itisdemonstratedthatanappropriateappliedvoltagepotentialacrossthepiezoelec-triclayerhastheeffectofcancellingeitherthereflectedorscatteredpressureoftheplateatanychosenfieldpointsinthefluid.

  • 标签:ACOUSTICREFLECTIONbaffledplateFINITEDIFFERENCE
  • 简介:Analyticalsolutionsfortheelasticpropertiesofavarietyofbinarynanotubeswitharbitrarychiralityareobtainedthroughthestudyofsystematicmolecularmechanics.Thismolecularmechanicsmodelisfirstextendedtochiralbinarynanotubesbyintroducinganadditionaloutof-planeinversiontermintotheso-calledstick-spiralmodel,whichresultsfromthepolarbondsandthebucklingofbinarygraphiticcrystals.Theclosed-formexpressionsforthelongitudinalandcircumferentialYoung’smodulusandPoisson’sratioofchiralbinarynanotubesarederivedasfunctionsofthetubediameter.Theobtainedinversionforceconstantsarenegativeforalltypesofbinarynanotubes,andthepredictedtubestiffnessislowerthanthatbytheformerstick-spiralmodelwithoutconsiderationoftheinversionterm,reflectingthesofteningeffectofthebucklingontheelasticpropertiesofbinarynanotubes.Theobtainedpropertiesareshowntobecomparabletoavailabledensityfunctionaltheorycalculatedresultsandtobechiralityandsizesensitive.ThedevelopedmodelandexplicitsolutionsprovideasystematicunderstandingofthemechanicalperformanceofbinarynanotubesconsistingofIII–VandII–VIgroupelements.

  • 标签:BINARYNANOTUBESELASTICpropertiesMolecularmechanics
  • 简介:Thelongitudinaloscillationofanonlinearelasticrodwithlateralinertiawasstudied.Basedonthefarfieldandsimplewavetheory,anonlinearSchrodinger(NLS)equationwasestablishedundertheassumptionofsmallamplitudeandlongwavelength.ItisfoundthatthereareNLSenvelopsolitonsinthissystem.FinallythesolitonsolutionoftheNLSequationwaspresented.

  • 标签:非线性弹性棒远声场NLS方程纵向振荡
  • 简介:Thebehaviorofthestressintensityfactoratthetipsofcrackssubjectedtouniaxialtensionσχ^∞=pwithtraction-freeboundaryconditioninhalf-planeelasticityisinvestigated.Theproblemisformulatedintosingularintegralequationswiththedistributiondislocationfunctionasunknown.Intheformulation,wemakeusedofamodifiedcomplexpotential.Basedontheappropriatequadratureformulastogetherwithasuitablechoiceofcollocationpoints,thesingularintegralequationsarereducedtoasystemoflinearequationsfortheunknowncoefficients.Numericalexamplesshowthatthevaluesofthestressintensityfactorareinfluencedbythedistancefromthecrackstotheboundaryofthehalf-planeandtheconfigurationofthecracks.

  • 标签:ELASTICHALF-PLANEMultiplecracksSINGULARintegral
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