Modeling of Inelastic Microstructure Development and Inhomogeneous Material Behaviour via Non-Convex Rate-Dependent Crystal Plasticity

The formulation of gradient inelasticity models has generally been focused on the effects of additional size-dependent hardening on the material behavior. Recently, the formulation of such models has taken a step in the direction of phase-field-like models. A prominent aspect of phase field models is the modeling of energetic microstructure interaction via non-convex contributions to the free energy of the system. In the current short work, the formulation of such free energy models and the corresponding IBVP using rate variational methods is briefly discussed. With the help of two simple models for such interaction non-convexity, it is shown that phenomena like stress relaxation after yielding as well as PLC-like serrated flow can be related to non-convexity and the corresponding inelastic deformation microstructure development.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen