A mixed elastoplastic/rigid-plastic material model

In forming process simulations, the rigid-plastic material model is widely used because of its numerically robust behaviour. The model yields accurate results, as long as the strain increments are large compared to the elasti c limit strain. In cases where the strain increments are small e.g. in dead metal zones or in case of elastic spring back the model is unstable or ina ccurate. In this paper a new integration algorithm is described for large strain pla stic deformations. The algorithm degenerates to the Euler forward elastopla stic model for small strain increments and to the rigid-plastic model for l arge strain increments. The model benefits from the advantages of both mode ls: accuracy and fast convergence over a large range of strain increments. The applicability of the method to forming process simulations is demonstra ted by several examples. Copyright (C) 1999 John Wiley & Sons, Ltd.