A RETURN MAPPING ALGORITHM FOR PLANE-STRESS AND DEGENERATED SHELL PLASTICITY

A numerical algorithm for plane stress and shell elasto-plasticity is presented in this paper. The proposed strain decomposition (SD) algori thm is an elastic predictor/plastic corrector algorithm, and in the co ntext of operator splitting, is a return mapping algorithm. However, i t differs significantly from other return mapping algorithms in that o nly the necessary response functions are used without invoking their g radients, and the stress increment is updated only at the end of the t ime step. This makes the proposed SD algorithm more suitable for mater ials with complex yield surfaces and will guard against error accumula tion during the time step. Comparative analyses of structural systems using the proposed strain decomposition (SD) algorithm and the iterati ve radial return (IRR) algorithm are presented. The results demonstrat e the accuracy and usefulness of the proposed algorithm.