1Example31TitleEigenvalueanalysisofashaftwiththreedisksDescriptionCalculatetheeigenvaluesofashaftwiththreedisks.StructuralgeometryVerificationExample2MODELAnalysisType3-DeigenvalueanalysisUnitSystemin,lbfDimensionLength30.0inRotationalmassmomentofinertia(Disk)Im1=Im2=Im3=10.0lbf-in⋅sec2ElementBeamelementMaterialModulusofelasticityE=1.04×107psiPoisson’sratioν=0.3SectionpropertyTorsionalstiffnessIxx=1.0in4BoundaryConditionNode4;ConstrainallDOFsNodes1~3;ConstrainDx,Dy,Dz,RyandRz.(OnlyRxallowed)AnalysisCaseRotationalmassmomentsofinertiaexistatthenodes1,2and3abouttheX-axis.Im=10.0lbf-in⋅sec2Numberofnaturalfrequenciestobecomputed=3Example313ResultsEigenvalueAnalysisResultsComparisonofResultsUnit:rad/secAngularvelocityTheoreticalMSC/NASTRANNISAIIMIDAS/Genω189.00089.00889.00889.008ω2249.400249.396249.400249.396ω3360.400360.388360.390360.388ReferencesWalterC.HurtyandMosheF.Rubinstein,“DynamicsofStructures”,EnglewoodCliffs,Prentice-Hall,Inc.,1964.“MSC/NASTRAN,VerificationProblemManual”,V.64,TheMacNeal-SchwendlerCorporation,1986,ProblemNo.V0303.“NISAII,VerificationManual”,Version91.0,EngineeringMechanicsResearchCorporation,1991.
