An evaluation of the explicit finite-element method approach for modelling dense flows of discrete grains in a Couette shear cell

Abstract

Granular flows are complex materials that are composed of discrete solid particles that can display gaseous, liquid, and/or solid behaviour under various conditions. Consequently, tribologists have studied them for their ability to carry loads and/or accommodate sliding surface velocities. Because of the highly non-linear behaviour of granular materials, their behaviour is difficult to predict. One new modelling approach that holds promise in simulating the behaviour of these particulate materials is the explicit finite-element method (FEM). The explicit FEM is a computational modelling approach capable of capturing dynamic, transient events, such as collisions and particle—particle interactions of grains in granular flows. This paper presents an explicit FEM simulation of a dense flow of steel particles in a rough gravity-free Couette shear cell with no externally applied load. Parametric tests of this cell are also carried out by varying the height of the shear cell and the types of known granular materials sheared in the cell. Subsequently, a final evaluation of the explicit FEM approach is conducted by simulating a dense flow of sheared titanium oxide (TiO₂) powder in the shear cell and comparing it to a similar simulation done using the discrete-element method (DEM) approach. In this comparison, the velocity of the flow in the DEM cell is larger, whereas the FEM and DEM solid fraction distributions are almost identical in the core regions of the shear cells. The merits of the FEM and DEM approaches are presented in light of the results shown in this work.