求解钢压杆极限承载力的有限条塑性系数增量初应力法

FINITE STRIP PLASTICITY COEFFICIENT INCREMENT INITIAL STRESS METHOD FOR SOLVING THE ULTIMATE CARRYING CAPACITY OF STEEL COLUMNS

本文提出了有限条塑性系数增量初应力法，用于分析钢压杆的弹塑性稳定极限承载力．该法采用分级加载，用有限条法建立结构的增量平衡方程；在塑性范围，引入截面的塑性系数对弹性刚度进行折减得到结构的弹塑性刚度矩阵；用修正的Ｎｅｗｔｏｎ－Ｒａｐｈｓｏｎ方法迭代求解．数值结果表明，本法效率较高，与钢压杆试验结果吻合良好，可以考虑残余应力和载荷偏心的影响，可望实现大型超静定结构的极限承载力分析．

This paper presents a numerical method called the finite strip plasticity coefficient increment initial stress method for sloving the ultimate load of elastic-plastic stability of steel columns.Step loading and finite strip principle are employed to establish the incremental equilibrium equation of structures.A plasticity coefficient of section is introduced to reducing the elastic stiffness matrix to obtain the elastic-plastic matrix of structures after the section goes into plasticity.The modified Newton-Raphson iterative technique is used to solve the equation, Numerical results show that the method is efficient,and the results are agree with that of experiment for welded Hsection steel columns.Using this method,the effects of residual stress and initial eccentricity of load can be considered at the same time.It is possible to analysis the ultimate loads of large structures by the method in this paper.