This article presents a new approach to grain fragmentation, its implementation in a discrete element method code, and an experimental validation. This approach is an improvement, compared with those models currently available in the literature. This new approach includes the use of polygonal particles, an estimation of stresses within the particles, a failure criterion, and a mode of rupture. The estimation of stresses is performed as a function of the forces exerted at the contacts, and the size and shape of the grains. The failure