Optimal description of two-dimensional complex-shaped objects using spheropolygons

Recent advances in the morphological description of particles in granular material systems allow twodimensional complex-shaped particles to be realistically simulated using spheropolygons, i.e., the Minkowski sum of a disk and a polygon. For identical numbers of vertices, spheropolygons achieve a better description of shapes than polygons, but require that the optimal spheroradius be determined. Here we propose amethod for generating spheropolygons that optimizes the description of particle morphologies, i.e., minimizes the error images and the numbers of vertices. Because the error images of individual particles are a proxy for the accuracy of granular matter flow calculations, while the numbers of vertices are a proxy for the computational time, the method is optimally applicable to discrete element methods. We demonstrate the proposed method using pebbles, gravel, and crushed shells.