Comparison of Beam Element and Shell Element in Analyzing Inherent Vibration of Structures

Finite element models of tube structures are set up using ANSYS with beam 188 element and shell63 element respectively.The computing programs are written by means of APDL language,the free vi-bration characteristics of tube structures with length-to-diameter ratios of 4~20 are computed.Also,the cor-responding inherent frequencies and modes are analyzed.The results show that as to tube structures with length-to-diameter larger than 10,the beam element of ANSYS based on Timoshenko beam can meet our re-quirements;but as to tube structures with length-to-diameter smaller than 6,in order to improve the accuracy,elements which are more close to real structures such as shell element or solid element should be used ac-cording to practical engineering.