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.