Computer Simulations and Experiment on the Quasi-Static Mechanics and Transport Properties of Granular Materials

Abstract

This article provides a brief review of the quasi-static mechanics of granular media, together with a summary of recent progess on the development of a quasi-static algorithm for the computer simulation of the mechanics and scalar-transport properties of random sphere assemblages. The algorithm involves several new techniques, including: a shuffling algorithm for rapidly generating random loose-packed assemblages; a microcell-adjacency method to further accelerate particle-contact search; a relaxation method to overcome the singularity in the quasi-linear system of equilibrium equations; and a simulated mechanical compression to generate random initial states of arbitrary packing density. The resulting program is versatile enough to simulate arbitrary deformation histories, for which both the mechanical and the scalar transport properties of sphere assemblages can be computed. An outline is given of the salient details of the mechanics algorithm together with a brief description of the analogous scalar transport computation for (electrical or thermal) conductivity. A brief summary is also given of the yield-stress and conductivity computations and their comparison against recent triaxial experimental tests on steel ball-bearing assemblages.