Force Chains

This movie shows the evolution of the load paths during the shearing of granular material. Experimentally, the technique of photoelasticity may be used to visualize the stress distribution in granular material. (For example, see Dan Howell's Research Page at Duke University.) Here the state of stress at every point is used to display this information for the numerical experiment. Red indicates highly stressed grains. Observe that the stressed grains line up in "force chains", and that the network of force chains evolves steadily with the shearing. Very similar results have been obtained experimentally by R. P. Behringer's group at Duke University.