Refined short-range interactions in the continuum dislocation-based model of plasticity at the microscale

The continuum dislocation-based model that describes the size-dependent plasticity at the microscale by considering evolving fields of curved dislocations is enhanced by a refined treatment of short-range interactions between dislocations. In addition to the Taylor-type stress, a back stress that takes into account the relative orientation of the interacting dislocations has been implemented in the model. Its influence on the physical content of the model as well as on its numerical character are investigated and the effect of the Taylor relation and back stress are compared. It appears that these two stresses can be considered as valid extremes for the description of the short-range interactions for high respectively low dislocation densities. Finally, the influence of the back stress on a previously presented interpretation of the so-called source-shortening effect by the present model is studied.