简介:Volterraseriesisapowerfulmathematicaltoolfornonlinearsystemanalysis,andthereisawiderangeofnonlinearengineeringsystemsandstructuresthatcanberepresentedbyaVolterraseriesmodel.Inthepresentstudy,therandomvibrationofnonlinearsystemsisinvestigatedusingVolterraseries.Analyticalexpressionswerederivedforthecalculationoftheoutputpowerspectraldensity(PSD)andinput-outputcross-PSDfornonlinearsystemssubjectedtoGaussianexcitation.Basedontheseexpressions,itwasrevealedthatboththeoutputPSDandtheinput-outputcrossPSDcanbeexpressedaspolynomialfunctionsofthenonlinearcharacteristicparametersortheinputintensity.Numericalstudieswerecarriedouttoverifythetheoreticalanalysisresultandtodemonstratetheeffectivenessofthederivedrelationship.TheresultsreachedinthisstudyareofsignificancetotheanalysisanddesignofthenonlinearengineeringsystemsandstructureswhichcanberepresentedbyaVolterraseriesmodel.
简介:Thisletterpresentsatheoreticalmodelofthenormal(head-on)collisionsbetweentwosoftspheresforpredictingtheexperimentalcharacteristicofthecoefficientofrestitutiondependentonimpactvelocity.Afterthecontactforcelawbetweenthecontactedspheresduringacollisionisphenomenologicallyformulatedintermsofthecompressionoroverlapdisplacementunderconsiderationofanelastic-plasticloadingandaplasticunloadingsubprocesses,thecoefficientofrestitutionisgainedbythedynamicequationofthecontactprocessonceaninitialimpactvelocityisinput.Itisfoundthatthetheoreticalpredictionsofthecoefficientofrestitutionvaryingwiththeimpactvelocityarewellinagreementwiththeexistingexperimentalcharacteristicswhicharefittedbytheexplicitformula.
简介:Inthispaper,ahigh-orderfinite-volumeschemeispresentedfortheone-dimensionalscalarandinviscidEulerconservationlaws.TheSimpson’squadratureruleisusedtoachievehigh-orderaccuracyintime.TogetthepointvalueoftheSimpson’squadrature,thecharacteristictheoryisusedtoobtainthepositionsofthegridpointsateachsub-timestagealongthecharacteristiccurves,andthethird-orderandfifth-ordercentralweightedessentiallynon-oscillatory(CWENO)reconstructionisadoptedtoestimatethecellpointvalues.Severalstandardone-dimensionalexamplesareusedtoverifythehigh-orderaccuracy,convergenceandcapabilityofcapturingshock.