验证例题36.pdf

1Example 36 Title 3-D single story frame structure Description Compute the natural frequencies of a 3-D single story frame structure.Structural geometry and analysis model Verification Example 2Model Analysis Type 3-D eigenvalue analysis Unit System in,lbf Dimension Length 27.25 in Width 17.25 in Height 18.625 in Mass M5 M8,M13 M18 =8.94223 10-3 lbfsec2/in M9 M12 =0.0253816 lbfsec2/in Element Beam element Material Modulus of elasticity E=27.9 106 psi Poissons ratio =0.3 Section Property Area A=1.074531 in2 Shear Area Asy=0.5372657 in2(=Asz)Torsional stiffness Ixx=1.331494 in4 Moment of inertia Iyy=0.665747 in4(=Izz)Boundary Condition Nodes 1 4 ;Constrain all DOFs.Analysis Case Convert the self weight to nodal masses and input manually.Number of natural frequencies to be computed=5 Example 36 3Results Eigenvalue Analysis Results Verification Example 4 1st vibration mode of the structure 5th vibration mode of the structure Example 36 5Comparison of Results Unit:Hz Natural frequency ANSYS SAP2000 NISA II MIDAS/Genf1 111.5 114.0 111.46 111.2 f2 115.9 119.0 116.10 115.8 f3 137.6 141.0 137.50 137.1 f4 218.0 222.0 216.20 215.7 f5 404.2 400.0 405.00 404.2 References I.S.Tuba and W.B.Wright,ASME Pressure Vessel and Piping 1972,“Computer Programs Verification”,ASME Publication I-24,Problem 1 “ANSYS,Engineering Analysis Verification Manual”,Revision 4.4,SWANSON Analysis Systems,Inc.,1990 “SAP90,A Series of Computer Programs for the Finite Element Analysis of Structures,Structural Analysis Verification Manual”,Computers and structures,Inc.,1992,Example 4 “NISA II,Verification Manual”,Version 91.0,Engineering Mechanics Research Corporation,1991