Hybrid dislocation dynamics based strain hardening constitutive model

•A new constitutive law accounting for glissile and stored dislocations simultaneously.•A constitutive model able to quantify dislocation junctions densities for junction types.•A new model suited for complex loading with extensive connection with discrete dislocation dynamics.

In this article, a Hybrid strain-hardening Model for slip driven plasticity is introduced. The model distinguishes between the contributions of glissile and stored dislocations, and polar and non-polar dislocations. The core idea relies on a two step-approach in which all glissile non-polar dislocations on given slip systems are represented by a virtual dislocation loop which evolution is modeled by a dislocation dynamics approach, while transformations of dislocations from glissile to stored, resulting from short-range dislocation–dislocation interactions, are based on phenomenological relations informed by dislocation dynamics simulations on dislocation pair interactions. The constitutive model developed should then allow for a reduction in fitting parameters and should be suitable to predict complex loading. Besides, the Hybrid Model is able to predict dislocation densities for all kinds of populations, including junctions. As a first application, the resulting Hybrid continuum/discrete dislocation density Model is utilized for predicting the stress–strain response of single crystal aluminum as a function of its orientation, slip activity, and junction formation.