A return-map algorithm for general associative isotropic elasto-plastic materials in large deformation regimes

The present paper addresses a flexible solution algorithm for associative i sotropic elasto-plastic materials, i.e. for materials whose elastic and pla stic behaviors are described through an isotropic free-energy function, an isotropic yield function and an associative flow rule. The discussion is re lative to a large deformation regime, while no hardening mechanisms are inc luded. The algorithm is based on a combination of the operator split method and a return map scheme. Both the algorithm linearization and the requirem ents for the yield criterion convexity are discussed in detail. Finally, to show the algorithm flexibility and performance, the discussion is speciali zed to three yield criteria and some test problems are studied. (C) 1999 El sevier Science Ltd. All rights reserved.