Capturing nonspherical shape of granular media with disk clusters

In discrete numerical modeling of granular materials, idealization of indiv idual particles is required, as it is not practical to model a large number of particles, each with its actual shape and size. To minimize computation times, researchers often use two-dimensional, circular elements. However, biaxial and direct shear tests on such specimens result in low strengths co mpared to granular materials, due, in part, to excessive rolling of the per fectly circular particles. In this paper, a new particle type, disk cluster s, is presented. A disk cluster is a group of circular disks permanently co nnected to form an irregularly shaped particle that more closely represents the shape of granular materials and has less tendency to rotate. Developme nt and implementation of disk cluster particles into a discontinuous deform ation analysis program is presented. Validations of the mechanics of a sing le disk cluster, biaxial shear, and anchor pullout simulations illustrate t he usefulness of this new particle type.