简介:Wavepropagationanalysisforafunctionallygradednanobeamwithrectangularcross-sectionrestingonvisco-Pasternak'sfoundationisstudiedinthispaper.Timoshenko'sbeammodelandnonlocalelasticitytheoryareemployedforformulationoftheproblem.TheequationsofmotionarederivedusingHamilton'sprincipalsbycalculatingkineticenergy,strainenergyandworkduetoviscoelasticfoundation.Theeffectsofvariousparameterssuchaswavenumber,non-homogeneousindex,nonlocalparameterandthreeparametersoffoundationareperformedonthephasevelocityofthenanobeam.Theobtainedresultsindicatethatsomeparameterssuchasnon-homogeneousindex,nonlocalparameterandwavenumberhavesignificanteffectontheresponseofthesystem.
简介:Byusingthebifurcationtheoryofdynamicalsystemstothecouplednonlinearwaveequations,theexistenceandstabilityofperiodicwavesolutionsbyHopfbifurcationsareobtained.Theoryoftravellingwavewasappliedtotransformakindofcouplednonlinearwaveequationsintothree-dimensiondynamicalsystems.Underdifferentparametricconditions,varioussufficientconditionstoguaranteetheexistenceandstabilityoftheabovesolutionsaregiven.
简介:Inthepaperthewaveattenuationinatwolayerfluidsystemisstudied.ThefluidinthetoplayerisidealandthatinthelowerlayeristheVoigtmodeloftheviscoelasticmedium.Adispersionrelationisderivedandtherateofthewavedecayiscomputed.Theapproximateexplicitexpressionsofthedecayratefordifferentwaterdeptharegiven,wheretheviscoelasticityiseitherverylargeorverysmall.Comparedwiththenumericalresults,ourresultsareveryaccurate,whichcanbeusedbyanengineer.
简介:Onthebasisofthemedicalandmechanicalanalysisandexplanationsinthispaperthevisco-elasticsimplysupportedbeammodelisproposedtotreatthedisplacementwaveofthebloodvessels.Therelationshipsbetweenthedisplacementwaveandbloodvesselelasticityaswellastheviscousdissipationofthebloodandbloodvesselareobtained.ThecorrespondingrelationsofsuchkindsofpulsesinthetraditionalChinesemedicineassmoothpulse,surfacepulseanddeeppulsetothedisplacementwavesofbloodvesselsarealsofound.Thecomputationalresultsareingoodagreementwiththoseacquiredintheexperimentswithultrasonicwave.
简介:Wavelettransformisaparticularlyusefultooltocharacterizetran-sientphenomenasuchaswavebreaking.Inthispaper,weapplywavelettransformtothedetectionandquantificationofthebreakingwaves.Weuseanewmethodthatusesthelocalpropertiesofwavelettransformtodetectandquantifythebreak-ingwavesandgivesomenewbreakingcriteria.Bycomparingthismethodwiththeclassicmethod,wefindthatwavelettransformisveryeffectiveinthedetectionofbreakingwaves.Withwavelettransform,asetofmeasuredwindwavedataisinves-tigated.Theresultshaverevealedsomepreviouslyunknownphenomenaaboutwavebreaking.
简介:InthispaperweextendthemethoddevelopedinforlimitingStokeswaveofinfinitewaterdepthtocoverthecaseoffinitedepth.Themethodhashighefficiencyandtheresultisaccurate.
简介:Withanincreasingemphasisonrenewableenergyresources,wavepowertechnologyisbecomingoneoftherealisticsolutions.However,the2011tsunamiinJapanwasaharshreminderoftheferocityoftheocean.Itisknownthattsunamisarenearlyundetectableintheopenoceanbutasthewaveapproachestheshoreitsenergyiscompressed,creatinglargedestructivewaves.Thequestionposedhereiswhetheranoscillatingwavesurgeconverter(OWSC)couldwithstandtheforceofanincomingtsunami.Severaltoolsareusedtoprovideananswer:ananalytical3Dmodeldevelopedwithintheframeworkoflineartheory,anumericalmodelbasedonthenon-linearshallowwaterequationsandempiricalformulas.Numericalresultsshowthatrun-upanddraw-downcanbeamplifiedundersomecircumstances,leadingtoanOWSClyingondryground!
简介:SomeofthemainprogressontheinvestigationofthemechanismofthewaveformationinexplosiveweldingattheInstituteofMechanicsissummarizedandotters’previousworksarere-viewed.OursystematicexperimentsandanalysisdonotsubstantiatethetheoryofwaveformationbasedonKarmanvortex-streetanalogyorHelmholtzinstability.Onthecontrary,theyshowthatmateri-alstrengthinsensitivetostrainrateplaysanimportantrole.Asimplehydro-plasticmodelispresentedtoexplainthemainfeaturesregardingtheinterracialwaveformationandtoestimatethemagnitudeofwavelength.Theresultisinbroadagreementwithexperiment.
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。
简介:Thelongitudinaloscillationofanonlinearelasticrodwithlateralinertiawasstudied.Basedonthefarfieldandsimplewavetheory,anonlinearSchrodinger(NLS)equationwasestablishedundertheassumptionofsmallamplitudeandlongwavelength.ItisfoundthatthereareNLSenvelopsolitonsinthissystem.FinallythesolitonsolutionoftheNLSequationwaspresented.
简介:AfastadaptivesymplecticalgorithmnamedMultiresolutionSymplecticScheme(MSS)wasfirstpresentedtosolvetheproblemofthewavepropagation(WP)incomplexmedia,usingthesymplecticschemeandDaubechies'compactlysupportedorthogonalwavelettransformtorespectivelydiscretisethetimeandspacedimensionofwaveequation.TheproblemwassolvedinmultiresolutionsymplecticgeometryspaceundertheconservativeHamiltoniansystemratherthanthetraditionalLagrangesystem.Duetothefascinatingpropertiesofthewaveletsandsymplecticscheme,MSSisapromisingmethodbecauseoflittlecomputationalburden,robustnessandrealityoflong-timesimulation.
简介:Bytakinginfiniteperiodicbeamsasexamples,themutualvariationalprincipleforanalyzingthefreewavepropagationinperiodicstructuresisestablishedanddemonstratedthroughtheuseofthepropaga-tionconstantinthepresentpaper,andthecorrespondinghierarchicalfiniteelementformulationisthende-rived.Thus,itprovidesthenumericalanalysisofthatproblemwithafirmtheoreticalbasisofvariationalprin-ciples,withwhichonemayconvenientlyillustratethemathematicalandphysicalmechanismsofthewaveprop-agationinperiodicstructuresandtherelationshipwiththenaturalvibration.Thesolutionisdiscussedandex-amplesaregiven.
简介:Thisletterpresentsanewanalyticalapproximationforwave(current)-induceddynamicsoilresponseinmarinesediments.Inthemodel,thethird-orderapproximationforwave-currentinteractionsisemployedfortheflowmodel,whileBiot’sdynamicporo-elasticmodelisusedtosimulatetheporousflowinaseabed.Thenewlyanalyticalsolutionisvalidatedwiththefieldobservations.Basedonthesolution,effectsofcurrentsandwave-nonlinearityonsoilresponseareexaminedandaparametricstudywillbecarriedouttoexaminetheinfluenceofcurrentsontheliquefactionpotential.
简介:Inthispaper,withPoincare’sformalism,andanindirectmethod,thecanonicalformsofthegeneralizedequationsofmotionduetoNielsenandCenovofaholonomicdynamicalsysteminthevelocity-phasespaceandtheacenleration-phasespaceareobtainedintermsofthePoincareparameters.
简介:Theassessmentofthewave-inducedsoilliquefactionplaysakeyroleinthegeotechnicaldesignforoffshorefoundations.Theunderlyingshortcomingsoftheexistingmomentaryliquefactioncriteriaareidentifiedandclarifiedbymechanismanalysesandtherecentfieldobservations.Amodifiedcriterionforthewave-inducedmomentaryliquefactionofasandyseabedisgiventodescribetheverticalporepressuredistributions.Animprovedapproximationofthemomentaryliquefactiondepthisfurtherpresented.Parametricstudyoftheeffectsofthesaturationdegreeofsoilsindicatesthatthismodificationissignificantfortheevaluationofwave-inducedmomentaryliquefaction.
简介:Asemi-analyticalmethodofsolvingtheproblemofdynamicstressconcentrationofarbitraryundergroundstructureundertheeffectofblastwaveswasintroduced.UsingtheFouriertransformtheory,theshockwaves(intheformsofSH-waves)canbeconvertedintofrequencybands.Afteremployingcomplexfunctionsandconformalmapping,theadmittancefunctionsofvariousundergroundstructureswereobtained.Then,theproblemofthetimedomaindynamicstressresponseofundergroundstructurecanbeeasilysolvedthroughtheFourierinversetransform.Atlast,theresultsandcurvesofthedynamicstressforthesquare,triangleandhorseshoecavitywerepresented.