Numerical approximations of problems in plasticity: error analysis and solution algorithms

The initial-boundary value problem of elastoplasticity is considered in the form of a variational inequality, with primary unknowns the displacement, plastic strain and internal variables. The well-posedness of this problem is reviewed, and results are presented for the convergence of a new fully discrete scheme, in which a non-differentiable functional characteristic of this problem is replaced by an appropriate discrete function. It is shown that convergence of this approximation is at the same rate as that for approximations based on the use of the original functional, and that the scheme is stable. Some iterative solution algorithms are discussed. © 1997 by John Wiley & Sons, Ltd.