Strain gradients played a vital role in the prediction of size-effects in the deformation behavior of metals at the micrometer scale. At this scale the behavior of metals strongly depended on the dislocation distribution. A dislocation density based strain gradient model was developed here which aimed to predict size-effects for structural components at this scale. For this model, the characteristic length was identified as the average distance of dislocation motion, which was deformation dependant and could be determined experimentally. The response of the model was compared to the strain gradient plasticity model of Huang et alia. It was shown that the present strain gradient model, which only required a physically measurable length-scale, could successfully predict size effects for a bar with an applied body force and for void growth.

A Dislocation Density Based Strain Gradient Model. S.Brinckmann, T.Siegmund, Y.Huang: International Journal of Plasticity, 2006, 22[9], 1784-97