ON THE LOADING/UNLOADING CONDITIONS OF INFINITESIMAL DISCRETE ELASTO-PLASTICITY
P. PAPADOPOULOS and R. L. TAYLOR Eng. Comp., 12, pp. 373-383, (1995)

Abstract
This paper addresses the loading/unloading conditions of the discrete initial-value problem of plastic flow at infinitesimal deformations. As in the continuum problem, it is established that the strain-space formulation of the loading conditions is primary. Generalized trapezoidal and mid-point rules are discussed. The loading conditions established for the general non-associated flow problem are shown to naturally reduce to well-known inequalities for flow rules obeying normality.