A finite element-based simulation of the microstructure evolution through a 3D finite strain Cosserat-phase-field model

Overview & Synopsis

This paper proposes a computational framework for microstructure evolution in three dimensions by coupling large deformation Cosserat isotropic hyperelasticity with a phase-field model to take into account grain boundary motion. At the microscale level, each material point has an associated crystal lattice orientation described through the Cosserat micro-rotation to which a parametrization has been assigned to tackle all possible singularities. Discretization by finite elements leads to a strongly nonlinear, coupled system that can be resolved using the classic Newton-Raphson method. In order to reduce computation time and effort, a parallel computing mechanism based on domain decomposition is adopted. To avoid the ill-conditioning inherent to the monolithic coupled system, an iterative staggered scheme was implemented to solve the approximate problem, whose convergence is achieved by setting a fixed point criterion characterized by stagnation of the phase-field variable.