Stresses in a Rapid, Simple Shear Flow of Granular Materials With Multiple Grain Sizes

A dense mixture of multiple-size disks or spheres are considered to flow in a simple shear motion. The stresses generated by the binary collisions among the particles are derived. It is quantitatively shown that as the size gradation widens, the stress reduction increases. A log-normal size distribution is used to demonstrate the effect of increasing standard deviation.