简介:Afinitedifferencemethodispresentedtosimulatetransversevibrationsofanaxiallymovingstring.Bydiscretizingthegoverningequationandtheequationofstress-strainrelationatdifferentfrictionalknots,twolinearsparsefinitedifferenceequationsystemsareobtained.Thetwoexplicitdifferenceschemescanbecalculatedalternatively,whichmakethecomputationmuchmoreefficient.Thenumericalmethodmakesthenonlinearmodeleasiertodealwithandoftruncationerrors,O(Δt~2+Δx~2).Italsoshowsquitegoodstabilityforsmallinitialvalues.Numericalexamplesarepresentedtodemonstratetheefficiencyandthestabilityofthealgorithm,anddynamicanalysisofaviscoelasticstringisgivenbyusingthenumericalresults.
简介:Theprincipleand1:3internalresonanceofarectangularthinplateinatransversemagneticfieldisinvestigated.Basedonthemagneto-elasticvibrationequationandelectromagneticforceexpressionsofthethinplates,thenonlinearmagneto-elasticvibrationdifferentialequationsofrectangularplatesunderexternalexcitationinatransversemagneticfieldarederived.Forarectangularplatewithonesidefixedandthreeothersidessimplysupported,thetwo-degree-offreedomnonlinearDuffingvibrationdifferen-tialequationsareproposedbythemethodofGalerkin.Themethodofmultiplescalesisadoptedtosolvethemodelequationsandobtainfourfirst-orderordinarydifferentialequationsgoverningmodulationoftheamplitudesandphaseanglesinvolvedviathefirst-orderorthesecond-orderprimary-internalreso-nances.Withanumericalexample,theamplitudefrequencyresponsecurves,timehistoryresponses,phaseportraitsandPoincaremapsofthefirsttwoordervibrationmodesviaprinciple-internalresonancearerespectivelycaptured.Andtheeffectsofexternalexcitationamplitudes,magneticfieldintensitiesandthicknessesonthevibrationofsystemarediscussed.Theresultsshowthattheresponseisdominatedbythelowmodewhenprinciple-internalresonanceoccurs.Theinternalresonanceprovidesamechanismfortransferringenergyfromahighmodetoalowmode.
简介:Ritzmethodisaneffectivewaywidelyusedtoanalyzethetransversebendingofthinrectangularplates.Itsaccuracydependscompletelyonthebasisfunctionsselected.Thispaperselectsthesuperpositionofsineserieswithpolynomialsasthebasisfunctionsofthinrectangularplates.Thecalculatingformulaearenotonlysimpleandeasilyprogrammed,butalsohavehighaccuracy.Finally,twonumericalresultsaregivenandcomparedwiththoseobtainedbytheclassicalmethod.
简介:Basedonthevariationandharmonicequationsandbytakingthemaximumamplitudeoftheshellcenterastheperturbationparameter,nonlinearvibrationofthinshallowconicshellsundercombinedactionofperipheralmomentandtransverseloadswassolved.Thelinearnaturalfrequencycanbegotbythefirst-orderapproximationandthemoreaccuratenonlinearfrequencyisgotbythesecond-orderapproximationundertheactionofstaticloads.Meanwhilethethird-orderapproximateanalyticexpressionisgivenfordescribingthenonlinearrelationbetweennaturefrequencyandperipheralmoment,transverseloads,amplitude,baseangleunderthesmalldeformation.Withinsomerange,thecomplexandregularityofthenonlinearrelationcanbedirectlyobservedfromthenumericresults.
简介:Thispaperdealswithfinitedeformationproblemsofcantileverbeamwithvariablesec-tionundertheactionofarbitrarytransverseloads.Bytheuseofamethodofvariablereplacement,thenonlineardifferentialequationwithvariedcoefficientfortheproblemcanbetransformedintoanequationwithvariableseparable.Theexactsolutioncanbeobtainedbytheintegrationmethod.Someexamplesaregiveninthepaper,andtheresultsoftheseexamplesshowthatthisexactsolutionincludestheexistingsolutionsinreferencesasspecialcases.