Interval elastoplastic analysis of structures

The present work considers the effects of uncertainties in a classical elastoplastic analysis. The uncertainties are related to the applied forces and the plastic material capacities, both of which are taken to lie within deterministic but bounded intervals. The primary aim is to obtain both upper and lower bound responses (e.g. of the displacement history). Our interval elastoplastic problem is formulated as an optimization problem which we refer to as an interval mathematical program with equilibrium constraints or interval-MPEC. We develop an efficient and robust algorithm to process such interval-MPEC accurately with any readily available nonlinear programming solver.