Center for Advanced Vehicular Systems

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Due to computer performances, atomic simulations are restricted to a few hundred millions of atoms. The upper bound for the volume of the investigated systems using molecular dynamics is therefore in the order of one tenth of µm³. Such a volume is large enough to investigate the interaction of a small number of dislocations but too small to look at the collective behavior of dislocations which is one mechanism at the origin of plastic deformation in metallic materials. At the engineering scale, plasticity is described using an internal state variable model. Nevertheless, these models are mainly phenomenological and consequently the physical meaning of the plasticity is lost. In order to develop dislocation based crystal plasticity models, discrete dislocation simulations were developed over the last fifteen years.

The aim of this work is to present a framework linking the collective behavior of dislocations to the macroscopic behavior of crystals using a concurrent framework. The foundations of the model will be introduced. The strength of the model will be illustrated by a set of examples such as (i) strengthening mechanisms introduced by irradiation, (ii) the link between microstructure and internal variables theories and (iii) materials behavior under extreme loading conditions.