On the validation of DEM and FEM/DEM models in 2D and 3D

Purpose - As particulate systems evolve, sliding, rolling and collision contacts all produce forces that discrete element method (DEM) methods aim to predict. Verification of friction rarely takes high priority in validation studies even though friction plays a very important role in applications and in mathematical models for numerical simulation. The purpose of this paper is to address sliding friction in finite element method (FEM)/DEM and rolling friction in DEM. Design/methodology/approach - Analytical solutions for block sliding were used to verify the authors' tangential contact force implementation of 2D FEM/DEM. Inspired by the kinetic art work Liquid Reflections by Liliane Lijn, which consists of free balls responding within a rotating shallow dish, DEM was used to simulate rolling, sliding and state-of-rest of spherical particles relative to horizontal and inclined, concave and flat spinning platforms. Various material properties, initial and boundary conditions are set which produce different trajectory regimes. Findings - Simulation output is found to be in excellent agreement when compared with experimental results and analytical solutions. Originality/value - The more widespread use of analytically solvable benchmark tests for DEM and FEM/DEM codes is recommended.