Effect of friction on the force distribution in sheared granular materials

The effect of friction on the quasi-static behavior of dense granular media is the subject of this work. The system is studied in a split-bottom ring shear cell, using Discrete Element Method simulations (DEM). When shear stress and deviatoric fabric are analyzed locally as functions of pressure and shear rate, they are found to increase with contact friction; saturation is reached for high friction with the strong contact network dominating. We start from this observation and look at the probability distribution functions (PDFs) of both normal and tangential forces. They behave in a similar fashion, i.e., the probability of weak forces and heterogeneity increase with friction. On the other hand, we find that the difference between the two directions (anisotropy) increases with friction in the case of normal forces, whereas it stays almost unaffected for tangential forces.