Reliable solution of a perfect plastic problem with uncertain stress-strain law and yield function

Coefficients of both the stress-strain relations and the yield function in the Prandtl-Reuss model are considered to be uncertain. Using simple finite elements in R-3 and backward differences in time, an approximate solution is defined and its continuous dependence on the uncertain data investigated. Three different criteria are chosen to find the worst possible data in a given set of admissible input data. Some convergence results are proven.