On implicit integration of bounding surface plasticity models

The bounding surface plasticity has become one of the most widely used frameworks of plasticity for modeling constitutive behavior of metals and soils, especially in cyclic loading. Due to special ingredients of the bounding surface plasticity, application of new integration techniques, generally devised for classical plasticity models, requires certain modifications. This paper describes the details of such modifications which are derived directly from the main equations underlying the bounding surface concept. Specifically the equation of flow rule is modified and a differential equation is derived to represent the evolution of a key factor, i.e. the ratio between the image stress and the current stress quantities. An implicit integration method is then used to integrate the full set of rate equations. Numerical simulations demonstrate the accuracy and efficiency of the proposed integration procedure in an application to a simple bounding surface version of the modified Cam clay model. (C) 1997 Elsevier Science Ltd.