简介:Basedonthetheoryofelasticdynamics,thescatteringofelasticwavesanddynamicstressconcentrationinfiber-reinforcedcompositewithinterfacesarestudied.Analyticalexpressionsofelasticwavesindifferentmediumareasarepresentedandananalyticmethodofsolvingthisproblemisestablished.Themodecoefficientsaredeterminedbymeansofthecontinuousconditionsofdisplacementandstressontheboundaryoftheinterfaces.Theinfluenceofmaterialpropertiesandstructuralsizeonthedynamicstresscon-centrationfactorsneartheinterfacesisanalyzed.Itindicatesthattheyhaveagreatinfluenceonthedynamicpropertiesoffiber-reinforcedcomposite.Asexamples,numericalresultsofdynamicstressconcentrationfac-torsneartheinterfacesarepresentedanddiscussed.Thispaperprovidesreliabletheoreticalevidenceforthestudyofdynamicpropertiesinfiber-reinforcedcomposite.
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。
简介:Metamaterialsareartificialcompositematerialsengineeredtohavepropertiesthatmaynotbefoundinnature.Byexploringlocallyresonanteffectofthebuildingunits,elasticmetamaterialsareabletopossessnegativevaluesofeffectivemass,effectivebulkorshearmodulus.Mass-springandcontinuummaterialversionsoftheseelasticmetamaterialsarereportedandthephysicalmechanismsofnegativeeffectiveparametersaredemonstrated.Applicationsofmetamaterialstoacousticcloakingandsuperlensingarealsodiscussed.
简介:Ifthefrequencyoftheincidentsoundwavecoincideswithoneoftheeigenfrequenciesoftheunderwaterelasticcylinder,thecorre-spondingeigenvibrationwillbeexcitedbyincidentsoundwaveandstronglyreradiatesoundwavetowardssurrondingwater.Ithasbeenre-vealedbypreviousinvestigationsthattheamplitudeofbackscatteringsoundappearstobeminimumattheeigenfrequenciesoftheunderwatermetalliccylindersbecauseofthedestructiveinterferencebetweenreradiatedwaveoftheeigenvibrationandthegeometricalreflectedwavefromsurfaceofthecylinders.Inthispaper,anewphenomenonhasbeenrevealed.Theamplitudeofbackscatteringsoundappearstobemaximumattheeigenfrequenciesofacylindermadefromnonmetallicmaterialinwhichthevelocityofelastictransversewaveislessthanthesoundvelocityinwater.
简介:Thedynamicresponseofthenon-linearelasticsimplysupportedbeamsubjectedtoaxialforcesandtransverseperiodicloadisstudied.Melnikovmethodisusedtoconsiderthedynamicbehav-iorofthesystemwhosepost-bucklingpathissteady.Theeffectofthehigherordertermsinthecon-trollingequationistakenintoaccount.Itisfoundthatthefifth-ordertermshaveagreatinfluenceonthedynamicbehaviorofthesystem.Theresultshowsthatthereexisteitherhomoclinicorbitsorhete-roclinicorbitsinthesystem.Inthispaper,thecriticalvaluesofthesystementeringchaoticstatesaregiven.Thediagramofanexampleisshown.
简介:ANALYSISOFSTABILITYONELASTICPLATESWITHINITIALIMPERFECTIONSXuKaiyu(徐凯宇)(ReceivedOct.5.1994;CommunicatedPaiLizhou)ANALYSISOFSTA...
简介:Withthehelpofthedeclinemethod,acomputer-aidedanalysisprogramofChristoffelequationisdes-cribedwhichmakesitpossibletocalculateelasticandviscousconstantsofcrystalspreciselyandeasily.TheelasticconstantsofLiNbO3andBi12GeO20crystalsarecalculatedwithanApple-ⅡcomputerandtheFortranprogramsuggested,andthecalculateddataarecomparedwiththevaluesachievedbyothers.
简介:Thispapergivesallthetwo-dimensionalmembranemodelsobtainedfromformalasymptoticanalysisofthethree-dimensionalgeometricallyexactnonlinearmodelofathinelasticshellmadewithaSaintVenant-Kirchhoffmaterial.Therefore,theothermodelscanbequotedasflexuralnonlinearones.Theauthoralsogivestheformalequationssolvedbytheassociatedstresstensorandpointsoutthatonlyoneofthosemodelsleads,bylinearization,tothe“classical”linearlimitingmembranemodel,whosejuetificationhasalreadybeenestablishedbyaconvergencetheorem.
简介:WeproposeanapplicationoftheelasticneuralnetforringrecognitioninRICHdetectors.Themethodhasbeendevelopedtofindringsdistortedduetomisalignmentofdetectorsandcontaminatedbynoise.ThealgorithmwastestedonsimulateddataofCOMPASSRICH-1detector.Reconstructionefficiencyis99.95%fortripleLEPTOeventstaking5msperevent.
简介:Thetransformationmethodtocontrolwaveshasreceivedwidespreadattentioninelectromagnetismandacoustics.However,thismachineryisnotdirectlyapplicabletothecontrolofelasticwaves,becauseithasbeenshownthattheNavier’sequationdoesnotusuallyretainitsformundercoordinatetransformation.Inthisletter,weprovetheforminvarianceoftheNavier’sequationundertheconformalmappingbasedontheHelmholtzdecompositionmethod.Theneededmaterialparametersareprovidedtomanipulateelasticwaves.Thevalidityofthisapproachisconfirmedbyanactivestealthdevicewhichcandisguisethesignalsourcebychangingitsposition.Experimentalverificationsandpotentialapplicationsmaybeexpectedinnondestructivetesting,structuralseismicdesignandotherfields.
简介:Wereportphotoelectronenergyspectraandangulardistributionsforionizationwithelasticscatteringinultrastronglaserfields.NoblegasspecieswithHartree–FockscatteringpotentialsshowareductioninelasticrescatteringwiththeincreasingenergyofultrastrongfieldsandwhentheLorentzdeflectionofthephotoelectronexceedsitswavefunctionspread.Therelativisticextensionofathree-steprecollisionmodeliswell-suitedtotheultrastrongintensityregime(>1017W∕cm2)thatliesbetweentraditionalstrongfieldsandextremerelativisticinteractions.
简介:Afinitedifference/boundaryintegralproceduretodeterminetheacousticreflectedpressurefromafluid-loadedbi-laminatedplateisdescribed.Thebi-laminateiscomposedofapiezoelectriclayerandanelasticlayerincontactwiththefluid,andisheldbyanacousticallyhardbaffle.Inthenumericalmodel,thefluidpressureatfluid/solidinterfaceisreplacedbyacontinuumofpointsourcesweightedbythenormalaccelerationoftheelasticplate,andthegoverningequationsystemissolvedinthesoliddomain.Withthenormalaccelerationfound,thereflectedpressureinthefluidisdeterminedbyanintegralexpressioninvolv-ingtheGreen’sfunction.Itisdemonstratedthatanappropriateappliedvoltagepotentialacrossthepiezoelec-triclayerhastheeffectofcancellingeitherthereflectedorscatteredpressureoftheplateatanychosenfieldpointsinthefluid.
简介:Analyticalsolutionsfortheelasticpropertiesofavarietyofbinarynanotubeswitharbitrarychiralityareobtainedthroughthestudyofsystematicmolecularmechanics.Thismolecularmechanicsmodelisfirstextendedtochiralbinarynanotubesbyintroducinganadditionaloutof-planeinversiontermintotheso-calledstick-spiralmodel,whichresultsfromthepolarbondsandthebucklingofbinarygraphiticcrystals.Theclosed-formexpressionsforthelongitudinalandcircumferentialYoung’smodulusandPoisson’sratioofchiralbinarynanotubesarederivedasfunctionsofthetubediameter.Theobtainedinversionforceconstantsarenegativeforalltypesofbinarynanotubes,andthepredictedtubestiffnessislowerthanthatbytheformerstick-spiralmodelwithoutconsiderationoftheinversionterm,reflectingthesofteningeffectofthebucklingontheelasticpropertiesofbinarynanotubes.Theobtainedpropertiesareshowntobecomparabletoavailabledensityfunctionaltheorycalculatedresultsandtobechiralityandsizesensitive.ThedevelopedmodelandexplicitsolutionsprovideasystematicunderstandingofthemechanicalperformanceofbinarynanotubesconsistingofIII–VandII–VIgroupelements.
简介:Thelongitudinaloscillationofanonlinearelasticrodwithlateralinertiawasstudied.Basedonthefarfieldandsimplewavetheory,anonlinearSchrodinger(NLS)equationwasestablishedundertheassumptionofsmallamplitudeandlongwavelength.ItisfoundthatthereareNLSenvelopsolitonsinthissystem.FinallythesolitonsolutionoftheNLSequationwaspresented.
简介:Thebehaviorofthestressintensityfactoratthetipsofcrackssubjectedtouniaxialtensionσχ^∞=pwithtraction-freeboundaryconditioninhalf-planeelasticityisinvestigated.Theproblemisformulatedintosingularintegralequationswiththedistributiondislocationfunctionasunknown.Intheformulation,wemakeusedofamodifiedcomplexpotential.Basedontheappropriatequadratureformulastogetherwithasuitablechoiceofcollocationpoints,thesingularintegralequationsarereducedtoasystemoflinearequationsfortheunknowncoefficients.Numericalexamplesshowthatthevaluesofthestressintensityfactorareinfluencedbythedistancefromthecrackstotheboundaryofthehalf-planeandtheconfigurationofthecracks.