A simple and efficient solution method for the limit elasto-plastic analysis of plane frames

摘要

A solution method for the first order step-by-step limit analysis of plane frames is presented. The formulation of the governing equations is based on the ‘plastic node’ method and takes into account stress reversals and any type of yield conditions. The solution of the governing equilibrium equations in each step is obtained with the preconditioned conjugate gradient method. Special attention is paid to the fact that the overall stiffness matrix changes gradually with the successive formation of ‘plastic nodes’. A number of test problems have been performed which show the usefulness of the present approach. The results also reveal the superiority of this technique, in both storage requirements and computing time, with respect to efficient methods of s