Grid Solver

What is the grid solver?

Actually, DAMASK contains three different grid solvers that are invoked with DAMASK_grid: Two Fast Fourier Transform (FFT)-based spectral solvers and one FEM solver. Which out of these three alternatives (spectral_basic, spectral_polarization, or FEM) is used in the calculation can be specified with the solver:mechanical key in the loadcase file. All three grid solvers operate on hexahedral volume elements discretized by a regular grid that is subjected to periodic boundary conditions. See Grid Solver/Load Case for more details.

Can I use the grid solver for non-periodic situations?

Not directly. Nevertheless, it is possible to break periodicity in certain directions by using a suitable constitutive model. A layer of soft dilatational material would, for example, result in (almost) zero stress conditions. Still, the mesh solver or MSC Marc are usually better options for non-periodic boundary conditions.