Large strain finite element analysis of sand: model, algorithm and application to numerical simulation of tire-sand interaction

Based on a review of several existing models for the elastic responses of g eomaterials, a new nonlinear elastic law is suggested. A fully implicit ret urn mapping algorithm for non-associative elastoplastic models of the geoma terials is presented within the regime of large strains. This algorithm is formulated in the principal axes. Algorithmic tangent moduli are derived. A modified critical state model in conjunction with the new nonlinear elasti c law is implemented into the general purpose finite element software MARC, using the proposed algorithm. Furthermore. the tire-sand interaction is nu merically simulated, employing the modified model and the algorithm. (C) 19 99 Elsevier Science Ltd. All rights reserved.