薄壁杆侧向稳定分析有限杆元模型

根据位移变分原理，建立有限杆元模型，对薄壁杆进行侧向稳定分析。在考虑截面扭转、翘曲同时，特别考虑了反映剪力滞后现象的杆壁中面上剪应交的影响。推导出薄壁杆侧向屈曲能量方程可适用求解常用边界条件，任意棱形截面形状的薄壁杆的屈曲特征值问题。

Finite member element model for lateral buckling of thin-walled members

The following two assumptions,made by Vlasov,are used to compute their deformations on the theory of thin-walled members stabillity:(a) rigid cross section;(b) No shearing strains in the middle surface of walls.The second assumption, based on pure torsion,is not suitable to non-uniform torsion.The shear lag phenomenon,induced by the shearing strains in the middle surface of walls,can be shown in some structures gravely.The present study is focused on establishing a finite member element model,based on energy principle,to estimate the lateral buckling capacity of thin-walled members.In the method the effects of torsion,warping and the shearing strains in middle surface of the walls are taken into account.Compared with the results from classical theory,energy method and finite element method,the numerical results demonstrate the efficiency of the proposed method.Because no need to introduce the concepts of shear centre and sectorial co-ordinate,the method is easily understood and applied.It is emphasized that the energy equation for buckling analysis is applicable for thinwalled members with any cross section.