An efficient and reliable technique is developed for finite element analysis of plane problems in the elasto-plastic regime. An enhanced integration algorithm based on the generalized midpoint rule is proposed to increase stability of convergency. In the algorithm, yield surfaces are linearized successively until the convergence is reached. A controlling technique for proper loading step size, which has been used in the arc-length method, is incorporated into the algorithm to reduce computing time. A computer program with these two attempts is developed for the analysis of elasto-plastic plane stress and plane strain problems and the results are compared with those obtained by the generalized midpoint rule, experimental data, rigid plastic analysis and the nonlinear analysis program ABAQUS.
The enhanced integration algorithm is shown to be more stable than existing ones especially in plane strain problems and the step size controlling technique reduces computing time greatly.