Force fluctuations in granular media

The forces in packed granular materials are distributed very differently than those in ''normal'' solids. Forces much larger than the mean occur, but are exponentially rare. These force inhomogeneities can be understood using an exactly solvable statistical model, in which the fluctuations in the forces arise because of variations in the contact angles together with the constraints imposed by the force balance on each grain. The details of this work are published elsewhere, see Liu et al. (1995) and Coppersmith et al. (1996).