简介:Parametricresonanceisoneofthemostimportantissuesinthestudyofdynamicalbehaviorofstructures.Inthispaper,dynamicinstabilityofamoderatelythickrectangularplateonanelasticfoundationisinvestigatedinthecaseofparametricandexternalresonancesduetoperiodicpassageofmovingmasses.Thegoverningcoupledpartialdifferentialequations(PDEs)ofthesystem,withconsiderationofthefirst-ordersheardeformationtheory(FSDT)orMindlinplatetheory,arepresentedandtheyarereducedtoasetofordinarydifferentialequations(ODEs)withtime-dependentcoefficientsusingtheGalerkinprocedure.Allinertialcomponentsofthemovingmassesareadoptedinthedynamicalformulation.Instabilitysurveyiscarriedoutforthreedifferentloadingtrajectoriesconsiderablyinterestedinmanypracticalapplicationsoftheissue,i.e.rectilinear,diagonalandorbitingtrajectories.Inordertoanalyzetheresonanceconditions,theincrementalharmonicbalance(IHB)methodisintroducedtocalculateinstabilityboundaries,aswellasexternalresonancecurvesinparametersplane.Acomprehensivestudyisdonetoassesseffectsofthicknessratioandfoundationstiffnessontheresonanceconditions.Itisfoundthatanincreaseintheplate'sthicknessratioleadstoareductioninvaluesofcriticalparameters.Moreover,itisobservedthatincreasingthefoundationstiffnessmovestheinstabilityregionsandresonaneecurvestohigherfrequenciesofthemovingmassesandalsoleadstofurtherstabilityoftheparametricallyexcitedsystematlowerfrequencies.TimeresponsesimulationsdoneviaRunge-KuttamethodconfirmedtheresultspredictedbyIHBmethod.