压弯钢构件在循环荷载作用下的非线性弯扭屈曲

本文根据非线性有限元的基本理论,采用基于修正的拉格朗日法描述的八节点超参数壳体单元,考虑几何非线性和材料非线性,结合混合强化本构关系,编制了非线性有限元计算程序。对压弯钢构件在循环荷载作用下的弹塑性弯扭屈曲进行计算机模拟,系统分析了H形截面压弯钢构件的滞回特性,以及翼缘宽厚比、腹板高厚比、构件轴压比和长细比对压弯钢构件弯扭屈曲的影响规律。通过对计算结果的比较,提出了强烈地震条件下,H形截面压弯钢构件在循环荷载作用下保持整体稳定,满足延性要求,具有较高屈曲后强度的长细比和板件宽厚比限值。

Nonlinear Flexural torsional Buckling Behavior of Steel StructureMembers Under Cyclic Bending and Constant Axial Force

This paper,based on the basic theory of nonlinear finite element and using the Updated Lagrange (U.L) formulation for the 8 node degenerate shell element in consideration of the nonlinearity of geometry and of material, sets up the double nonlinear finite element equations and establishes the nonlinear finite element analysis program according to the mixed strengthened constitutive relations. Computerized modeling of flexural torsional buckling behavior of steel structure members under constant axial force and cyclic bending are carried out. The hysteretic characteristics of H section columns subjected to constant axial compressive force and cyclic bending moment are analyzed systematically. The regularity of the effects of width to thickness ratio of flange,height to thickness ratio of web, axial compression ratio and slenderness ratio of the structure member under cyclic loading on flexural torsional buckling behavior are obtained. Then by comparing the results of analysis,the limit values of width to thickness ratio and slenderness ratio of the H section members to keep the flexural torsional buckling structure members steady under cyclic loading and to meet the requirements of ductility and strength after buckling under strong seismic action are also suggested.