Energy-Based Analysis of Effect of Inter-particle Friction on the Shear Behavior of Granular Materials

This paper describes a numerical investigation on the effect of inter-particle friction on the shear behavior of granular materials, with an emphasis placed on an energy-based analysis. The numerical simulation results show that the peak friction angle \( \phi_{p} \) increases with the inter-particle friction angle \( \phi_{\mu } \), and that the constant-volume friction angle \( \phi_{cv} \) increases with \( \phi_{\mu } \) in the low friction region before reaching a plateau stage at the high friction region, with the division point of such two characteristic stages emerging between \( \mu_{s} \) = 0.3 and \( \mu_{s} = 0.5 \). The energy-based analyses indicate that inter-particle friction exerts a profound effect on the energy dissipation and storing of granular assemblies. The inter-particle friction behavior and damping mechanism are the two major means in the consumption of the external work input. Frictional dissipation increases at first with the inter-particle friction coefficient in the low friction region, and then decreases in the high friction region, with the damping consumption exhibiting a reverse variation manner. The mobilized shear strength depends primarily on the energy stored in the normal direction at the contacts, E _pn , which demonstrates the same variation mode as the deviatoric stress and constant-volume friction angle, despite that the energy stored in the tangential direction at the contacts, E _pt , as well as the mobilized friction coefficient \( \mu_{b} \), shows a monotonic increase with the inter-particle friction coefficient.