IMPULSE STRENGTHS IN RAPID GRANULAR SHEAR FLOWS

This paper describes measurements of the impulses that particles experience while undergoing rapid shear. These were performed with an eye towards understanding the processes that lead to particle attrition and fracture. The measurements were taken from a discrete particle computer simulation of a simple shear flow of spheres. Special attention is paid to the strongest impulses as these will do the most damage. The results indicate that the largest impulses arise, not from the mean shear flow, but from the random particle velocities that are characterized by the so-called ''granular temperature''. Measurements of the largest impulses are presented as functions of particle properties and solid concentration. Histograms of the impulse strengths illustrate the effect of concentration and particle surface friction. Finally, geometric distributions are presented that illustrate the shear induced anisotropy in the impulse strengths.