The Burgers vector and the flow of screw and edge dislocations in finite-deformation single-crystal plasticity

We consider finite plasticity based on the decomposition F = (FFp)-F-e of the deformation gradient F into elastic and plastic distortions F-e and F-p (det F-p = 1). Within this framework the macroscopic Burgers vector may be characterized by the tensor field G = F-p Curl F-p. We derive a natural convected rate for G associated with evolution of F-p and as our main result show that, for a single-crystal, temporal changes in G-as characterized by its convected time derivative-may be decomposed into temporal changes in distributions of screw and edge dislocations on the individual slip systems. We discuss defect energies dependent on the densities of these distributions and show that corresponding thermodynamic forces are macroscopic counterparts of classical Peach-Koehler forces. (c) 2006 Published by Elsevier Ltd.