Non Smooth Contact Dynamics (NSCD) [1] has shown its efficiency in the simulation of granular media. Since the number of particles and contacts increases or/and the shape of discrete elements becomes more complex, numerical tools need to be improved to keep a reasonable CPU computation time. A first step in this direction has been performed in [2] by the parallelization of the NSCD contact solver. A second step consists in introducing a domain decomposition method adapted to the diffuse non-regularity of granular media. The aim of this presentation is to validate decomposition domain simulations of granular media, as regards of physical key points, on an academic test.