ABSTRACT
R. Castellanza & R. Nova Milan University of Technology (Politecnico), Milan, Italy
ABSTRACT: The paper presents an extension of the classical Generalized Backward Euler (GBE) return mapping algorithm to a general class of elastoplastic constitutive equations for geomaterials characterized by both mechanical and non-mechanical hardening mechanisms.Akey point of the proposed integration procedure is in the modification of the classical additive split of the evolution problem by extending the elastic predictor stage in order to account for non-mechanical effects. Restriction to isotropic behavior allows to formulate the return mapping algorithm in the space of principal elastic strains. The resulting integration scheme is well suited for the application to relatively complex, three-invariant yield surface and plastic potential functions, and, remarkably, can be linearized in closed form. As an example, the application of the general procedure is discussed with reference to the constitutive model for chemical weathering of bonded geomaterials recently presented by Tamagnini et al. (2002). A series of numerical experiments are given to illustrate the accuracy and convergence properties of the algorithm.
