10 Pages

Force transmission in granular media

Powders, and other granular media composed of discrete particles, exhibit very complex non-linear, hysteretic, stress-strain behaviour which is both stress level and stress path dependent. The complex­ ity arises from the fact that the ensemble macro­ scopic response is a function of the spatial, size and shape distributions of the constituent particles and the distributions of other internal variables as­ sociated with the interactions between contiguous particles. The macroscopic state of stress is a func­ tion of the distribution of contact forces, Thornton and Barnes [1], and the ensemble moduli are related to the distribution of contact stiffnesses, Thornton [2]. The distribution of contact forces is also relevant to the fracture and crushing of constit­ uent particles. The contact stiffnesses are functions of the contact areas and the distribution of contact areas controls the conductivity of granular media. Since the contact areas and contact stiffnesses are themselves functions of the contact forces, it is of scientific and industrial interest to understand how the intrinsic properties of the constituent particles affects the force transmission in granular media.