INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS The Role of Nonlinear Hardening/Softening in Probabilistic Elasto-Plasticity Kallol Sett, Boris Jeremi´ c * and M. Levent Kavvas Department of Civil and Environmental Engineering, University of California, Davis, CA 95616 Accepted for publication 1. ABSTRACT The elastic–plastic modeling and simulations have been studied extensively in the last century. However, one crucial area of material modeling has received very little attention. The uncertainties in material properties probably have the largest influence on many aspects of structural and solids behavior. Despite its importance, effects of uncertainties of material properties on overall response of structures and solids have rarely been studied. Most of the small number of studies on effects of material variabilities have used repetitive deterministic models through Monte–Carlo type simulations. While this approach might appear sound, * Correspondence to: Boris Jeremi´ c, Department of Civil and Environmental Engineering, University of California, One Shields Ave., Davis, CA 95616, jeremic@ucdavis.edu