学科分类
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72 个结果
  • 简介:Wavepropagationanalysisforafunctionallygradednanobeamwithrectangularcross-sectionrestingonvisco-Pasternak'sfoundationisstudiedinthispaper.Timoshenko'sbeammodelandnonlocalelasticitytheoryareemployedforformulationoftheproblem.TheequationsofmotionarederivedusingHamilton'sprincipalsbycalculatingkineticenergy,strainenergyandworkduetoviscoelasticfoundation.Theeffectsofvariousparameterssuchaswavenumber,non-homogeneousindex,nonlocalparameterandthreeparametersoffoundationareperformedonthephasevelocityofthenanobeam.Theobtainedresultsindicatethatsomeparameterssuchasnon-homogeneousindex,nonlocalparameterandwavenumberhavesignificanteffectontheresponseofthesystem.

  • 标签: 弹性波传播 功能梯度 基础 TIMOSHENKO 非局部弹性理论
  • 简介:Byusingthebifurcationtheoryofdynamicalsystemstothecouplednonlinearwaveequations,theexistenceandstabilityofperiodicwavesolutionsbyHopfbifurcationsareobtained.Theoryoftravellingwavewasappliedtotransformakindofcouplednonlinearwaveequationsintothree-dimensiondynamicalsystems.Underdifferentparametricconditions,varioussufficientconditionstoguaranteetheexistenceandstabilityoftheabovesolutionsaregiven.

  • 标签: 行波解 HOPF分歧 非线性方程 存在性 稳定性
  • 简介:Inthepaperthewaveattenuationinatwolayerfluidsystemisstudied.ThefluidinthetoplayerisidealandthatinthelowerlayeristheVoigtmodeloftheviscoelasticmedium.Adispersionrelationisderivedandtherateofthewavedecayiscomputed.Theapproximateexplicitexpressionsofthedecayratefordifferentwaterdeptharegiven,wheretheviscoelasticityiseitherverylargeorverysmall.Comparedwiththenumericalresults,ourresultsareveryaccurate,whichcanbeusedbyanengineer.

  • 标签: water WAVE WAVE in STRATIFIED FLUID
  • 简介:Onthebasisofthemedicalandmechanicalanalysisandexplanationsinthispaperthevisco-elasticsimplysupportedbeammodelisproposedtotreatthedisplacementwaveofthebloodvessels.Therelationshipsbetweenthedisplacementwaveandbloodvesselelasticityaswellastheviscousdissipationofthebloodandbloodvesselareobtained.ThecorrespondingrelationsofsuchkindsofpulsesinthetraditionalChinesemedicineassmoothpulse,surfacepulseanddeeppulsetothedisplacementwavesofbloodvesselsarealsofound.Thecomputationalresultsareingoodagreementwiththoseacquiredintheexperimentswithultrasonicwave.

  • 标签: WAVE simply RELAXATION RADIAL CONSTRAINT DISSIPATION
  • 简介:Wavelettransformisaparticularlyusefultooltocharacterizetran-sientphenomenasuchaswavebreaking.Inthispaper,weapplywavelettransformtothedetectionandquantificationofthebreakingwaves.Weuseanewmethodthatusesthelocalpropertiesofwavelettransformtodetectandquantifythebreak-ingwavesandgivesomenewbreakingcriteria.Bycomparingthismethodwiththeclassicmethod,wefindthatwavelettransformisveryeffectiveinthedetectionofbreakingwaves.Withwavelettransform,asetofmeasuredwindwavedataisinves-tigated.Theresultshaverevealedsomepreviouslyunknownphenomenaaboutwavebreaking.

  • 标签: WAVELET WAVE BREAKING CRITERIA
  • 简介:InthispaperweextendthemethoddevelopedinforlimitingStokeswaveofinfinitewaterdepthtocoverthecaseoffinitedepth.Themethodhashighefficiencyandtheresultisaccurate.

  • 标签: STOKES WAVE LIMITING WAVE OPTIMIZATION
  • 简介:Withanincreasingemphasisonrenewableenergyresources,wavepowertechnologyisbecomingoneoftherealisticsolutions.However,the2011tsunamiinJapanwasaharshreminderoftheferocityoftheocean.Itisknownthattsunamisarenearlyundetectableintheopenoceanbutasthewaveapproachestheshoreitsenergyiscompressed,creatinglargedestructivewaves.Thequestionposedhereiswhetheranoscillatingwavesurgeconverter(OWSC)couldwithstandtheforceofanincomingtsunami.Severaltoolsareusedtoprovideananswer:ananalytical3Dmodeldevelopedwithintheframeworkoflineartheory,anumericalmodelbasedonthenon-linearshallowwaterequationsandempiricalformulas.Numericalresultsshowthatrun-upanddraw-downcanbeamplifiedundersomecircumstances,leadingtoanOWSClyingondryground!

  • 标签: 转换器 振荡波 海啸 浪涌 可再生能源 发电技术
  • 简介:SomeofthemainprogressontheinvestigationofthemechanismofthewaveformationinexplosiveweldingattheInstituteofMechanicsissummarizedandotters’previousworksarere-viewed.OursystematicexperimentsandanalysisdonotsubstantiatethetheoryofwaveformationbasedonKarmanvortex-streetanalogyorHelmholtzinstability.Onthecontrary,theyshowthatmateri-alstrengthinsensitivetostrainrateplaysanimportantrole.Asimplehydro-plasticmodelispresentedtoexplainthemainfeaturesregardingtheinterracialwaveformationandtoestimatethemagnitudeofwavelength.Theresultisinbroadagreementwithexperiment.

  • 标签: INTERFACE WAVES INSTABILITY of INTERFACE EXPLOSIVE
  • 简介:在电子上控告的喷气的非线性的不稳定性用描述一口液体喷气拉长并且变瘦的管理电镀物品水动力学方程被学习。到空间和时间演变骚乱的一个喷气流动系统题目被考虑。在线性阶段,瑞利和进行的喷气流动不稳定性模式被揭开。在流动的非线性的不稳定性经由三个一组被探索揭开的反响的波浪fa-vorable操作模式不以前在这个问题的线性学习检测了。特别地,喷气半径显著地被减少,并且喷气的电场在非线性的学习下面是适当地面向的。考虑回声三个一组模式提供对由于正切的电场效果拉长并且变瘦的一口喷气的更好数学的描述,这被发现。在喷气流动系统的线性、非线性的不稳定性结果被介绍并且讨论。

  • 标签: 非线性的波浪相互作用 三个一组波浪 时间空间的不稳定性
  • 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:AfastadaptivesymplecticalgorithmnamedMultiresolutionSymplecticScheme(MSS)wasfirstpresentedtosolvetheproblemofthewavepropagation(WP)incomplexmedia,usingthesymplecticschemeandDaubechies'compactlysupportedorthogonalwavelettransformtorespectivelydiscretisethetimeandspacedimensionofwaveequation.TheproblemwassolvedinmultiresolutionsymplecticgeometryspaceundertheconservativeHamiltoniansystemratherthanthetraditionalLagrangesystem.Duetothefascinatingpropertiesofthewaveletsandsymplecticscheme,MSSisapromisingmethodbecauseoflittlecomputationalburden,robustnessandrealityoflong-timesimulation.

  • 标签: 小波变换 自适应耦对算法 波动力学 波传播 哈密顿系统 复合介质
  • 简介:Bytakinginfiniteperiodicbeamsasexamples,themutualvariationalprincipleforanalyzingthefreewavepropagationinperiodicstructuresisestablishedanddemonstratedthroughtheuseofthepropaga-tionconstantinthepresentpaper,andthecorrespondinghierarchicalfiniteelementformulationisthende-rived.Thus,itprovidesthenumericalanalysisofthatproblemwithafirmtheoreticalbasisofvariationalprin-ciples,withwhichonemayconvenientlyillustratethemathematicalandphysicalmechanismsofthewaveprop-agationinperiodicstructuresandtherelationshipwiththenaturalvibration.Thesolutionisdiscussedandex-amplesaregiven.

  • 标签: free wave propagation PERIODIC structures NON-SELF-ADJOINT
  • 简介:Thisletterpresentsanewanalyticalapproximationforwave(current)-induceddynamicsoilresponseinmarinesediments.Inthemodel,thethird-orderapproximationforwave-currentinteractionsisemployedfortheflowmodel,whileBiot’sdynamicporo-elasticmodelisusedtosimulatetheporousflowinaseabed.Thenewlyanalyticalsolutionisvalidatedwiththefieldobservations.Basedonthesolution,effectsofcurrentsandwave-nonlinearityonsoilresponseareexaminedandaparametricstudywillbecarriedouttoexaminetheinfluenceofcurrentsontheliquefactionpotential.

  • 标签: 海洋沉积物 电流 土壤 反应 流量模型 动态变化
  • 简介:Inthispaper,withPoincare’sformalism,andanindirectmethod,thecanonicalformsofthegeneralizedequationsofmotionduetoNielsenandCenovofaholonomicdynamicalsysteminthevelocity-phasespaceandtheacenleration-phasespaceareobtainedintermsofthePoincareparameters.

  • 标签: HOLONOMIC DYNAMIC SYSTEM Nielsen’s EQUATIONS of
  • 简介:Theassessmentofthewave-inducedsoilliquefactionplaysakeyroleinthegeotechnicaldesignforoffshorefoundations.Theunderlyingshortcomingsoftheexistingmomentaryliquefactioncriteriaareidentifiedandclarifiedbymechanismanalysesandtherecentfieldobservations.Amodifiedcriterionforthewave-inducedmomentaryliquefactionofasandyseabedisgiventodescribetheverticalporepressuredistributions.Animprovedapproximationofthemomentaryliquefactiondepthisfurtherpresented.Parametricstudyoftheeffectsofthesaturationdegreeofsoilsindicatesthatthismodificationissignificantfortheevaluationofwave-inducedmomentaryliquefaction.

  • 标签: 土壤液化 沙质海床 标准 瞬间 波浪 压力分布
  • 简介:Asemi-analyticalmethodofsolvingtheproblemofdynamicstressconcentrationofarbitraryundergroundstructureundertheeffectofblastwaveswasintroduced.UsingtheFouriertransformtheory,theshockwaves(intheformsofSH-waves)canbeconvertedintofrequencybands.Afteremployingcomplexfunctionsandconformalmapping,theadmittancefunctionsofvariousundergroundstructureswereobtained.Then,theproblemofthetimedomaindynamicstressresponseofundergroundstructurecanbeeasilysolvedthroughtheFourierinversetransform.Atlast,theresultsandcurvesofthedynamicstressforthesquare,triangleandhorseshoecavitywerepresented.

  • 标签: 动态应力 爆振波 FFT转换 秘密结构 准解析法