Conventional continuum mechanics models of inelastic deformation processes are size scale independent. In contrast, there is considerable experimental evidence that plastic flow in crystalline materials is size dependent over length scales of the order of tens of microns and smaller. At present there is no generally accepted framework for analyzing the size-dependent response of a plastically deforming crystal. Dislocation based plasticity can provide information on the form of the governing equations and the boundary conditions, as well as material properties. Solutions obtained using discrete dislocation plasticity and several recently proposed nonlocal continuum formulation are compared. The implications for modeling size dependent plasticity are discussed.
