The relationships between mesoscopic plastic strain gradients, geometrically necessary dislocations and dislocation dynamics were considered. It was argued that the connection between geometrically necessary dislocations, and size effects, in crystal plasticity should be established on the basis of dislocation dynamics; taking into account specific deformation conditions. It was demonstrated that dislocation dynamics-based models for size effects led to the various phenomenological forms of gradient plasticity laws proposed in the literature.

Geometrically Necessary Dislocations and Strain Gradient Plasticity - a Dislocation Dynamics Point of View. M.Zaiser, E.C.Aifantis: Scripta Materialia, 2003, 48[2], 133-9