简介：Thealmostsurestabilityofhomogeneousviscoelasticplatessubjectedtoarandomwide-bandstationaryin-planeloadisinvestigated.TheviscoelasticbehavioroftheplateisdescribedintermsoftheBo-ltzmannsuperpositionprinciple,therelaxationkernelsofwhicharerepresentedbythesumsofexponents.Ontheassumptionthatthein-planeloadisrandomwide-bandstationaryprocess,sufficientconditionsforal-mostsurestabilityofviscoelasticplatesareobtainedbytheapplicationsofLyapunov’sdirectmethod.

简介：Thispaperappliesthestochasticfiniteelementmethodtoanalysethestatisticsofstressesinearthdamsandassessthesafetyandreliabilityofthedams.Formulationsofthestochasticfiniteelementmethodarebrieflyreviewedandtheprocedureforassessingdam’sstrengthandstabilityisdescribed.Asanexample,adetailedanalysisforanactualdam-Nululindamisperformed.Apracticalmethodforstudyingbuilt-damsbasedontheprototypeobservationdataisdescribed.

简介：ThispaperpresentsanattemptattheapplicationofcatastrophetheorytothestabilityanalysisofJ-controlledcrackgrowthinthree-pointbendingspecimens.ByintroducingthesolutionsofJ-integralinthecompletelyyieldingstatefortheidealplasticmaterial,thecriticalconditionoflosingstabilityforthecrackpropagationinthespecimenisobtained,basedonthecuspcatastrophetheory.Theprocessofthecrackgrowthfromgeometricalsenseisdescribed.

简介：BasedontheFloquettheoryonordinarydifferentialequationswithperiodicallyvariablecoefficientsandthebifurcationapproachtononlinearequations,anumericalapproachtodeterminingthestabilityregionofcontrolparametersisestablishedforadynamiccontrolsystemcomposedofamovingbodylevitatedmagneticallyoverflexibleguideways.Thesystemisnonlinearlycoupledamongtheelasticdeformationofguideways,disturbancethelevitationpositionofthebodyandelectromagneticcontrolforces.Thenumericalsimulationisgivenforthesysteminthecaseinwhichthecontrolparametersaretakenwithinandoutofthestabilityregionrespectively.Resultsshowthatthisapproachisreliable.