  A remarkable feature of static granular matter is the distribution of force
along intricate networks. Even regular inter-particle contact networks produce
wildly inhomogeneous force networks where certain "chains" of particles carry
forces far larger than the mean. In this paper, we briefly review past
theoretical approaches to understanding the geometry of force networks. We then
investigate the structure of experimentally-obtained granular force networks
using a simple algorithm to obtain corresponding graphs. We compare our
observations with the results of geometric models, including random bond
percolation, which show similar spatial distributions without enforcing vector
force balance. Our findings suggest that some aspects of the mean geometry of
granular force networks may be captured by these simple descriptions.
