Verification of the Double Slip and Rotation Rate Model for Elliptical Granular Flow Using the Distinct Element Method

The investigation in this paper focuses on the numerical verification of the double slip and rotation rate model (DSR2 model) for elliptical particles by the discrete element method (DEM). The averaged micro-pure rotation rate (APR) based on the relative movement of contact between two ellipses has been firstly deduced, then the variable was introduced into the DSR2 model, which is originally proposed for plastic flow of granular assemblages. A developed DEM code NS2D was used to generate assemblages that were composed of elliptical particles with aspect ratio of 1.4 and 1.7, respectively. Then undrained simple shear tests on these samples were conducted to reproduce the plastic flow of elliptical particles and validate the DSR2 model. The results show that the DSR2 model appears to be able to predict the variation of angular velocity in kinematic models of both circular and elliptical particle assemblies, and the variable APR is a rational and important parameter, which considers the effect of particle rotation in the energy dissipation process and bridges discrete and continuum granular mechanics.