(320h) Effects of Particle Size and Shape on Granular Shear Flows in Shear Cells

In this study, shear flows of non-spherical particles of different sizes and shapes are investigated in both Jenike and Schulze Ring Shear Cells. The effects of particle size and particle shape are explored and the difference between these two shear cells are investigated. The discrete element method (DEM) is also applied to model the shear flows in the ring shear cell, in order to explore the underlying mechanism of the shear flows and the effect of the influential factors. Results show that shear stresses measured from Jenike and Schulze Ring Shear Cells are basically identical. Solid fraction and shear stress predicted from DEM simulations are consistent with those measured from shear cell experiments. It is found that for particles with same Aspect Ratio (AR), the solid fraction decreases with the increasing particle size, leading to a decreased shear stress with increasing particle size. It is also found that the shear stress decreases with increasing AR. Specifically for cylindrical particles with the same bottom diameter (0.5 mm × 2 mm and 0.5 mm × 4 mm), more elongated particles have a smaller stress ratio. It is believed that the packing structure and particle orientation play an important role on the shear stress.