Comparison of different models for tangential forces using the particle dynamics method

This work is a study on the formation of piles of granular materials using the particle dynamics method. Different models of tangential forces were examined for the analysis of stability of the pyramid of two-dimensional grains. The critical value of the coefficient of friction between grains at which a pyramid is stable was calculated. The value of the angle of repose, i.e., the angle below which the sand pile is stationary, was calculated and compared with numerical simulations using various particles interaction models and experimental results. It was found that the model of the tangential force for which the pyramid is stable with the correct value of the coefficient of friction also yields the magnitude of the angle of repose more close to the experimental values.