A composite particle model for non-spherical particles in DEM simulations

This paper presents a composite particle model with sphere clumps for modelling non-spherical particles in discrete element method (DEM) simulations. The formulation of the sphere clumps uses random selections of particle radii and positions, thus it can theoretically simulate all possible non-spherical particles encountered in engineering projects. In this study, the generation of sphere clumps in space was discussed in detail, and different particle non-sphericities were compared. This numerical model has been employed to study the shear behaviour of granular assemblies under undrained triaxial compression conditions. It is evident that the use of composite particle model in the DEM can largely increase the shear strengths of granular assemblies. For granular samples consisting of various types of sphere clumps, different mechanical responses have been observed. In particular, the sphere clumps with high non-sphericity can lead to very high peak/residual shear strength, and high material internal friction angle. The use of sphere clumps mixture can modulate the shear behaviour, with its mechanical properties being close to those of real quartz sand grains.