LAUSR

The superquadric function is employed to represent spherical and non-spherical particles. Although particles with different aspect ratios and surface blockiness can be described using the superquadric equation, the shapes of these particles are geometrically symmetric and further engineering applications are limited. In this work, a poly-superquadric element based on the superquadric function is developed. This model is composed of eight one-eighth superquadric elements and is used to represent superquadric elements, poly-ellipsoids, and asymmetrically shaped particles. To examine the validity of the poly-superquadric DEM model, the numerical results of a hemisphere impacting a plane are obtained and compared with the theoretical results. Then, the mass flow rates of particles of different shapes are investigated. The results show that the spheres have the fastest flow rate, and the flow rate of the pebble-shaped particles constructed by the poly-superquadric elements is faster than that of the cube-like particles. Moreover, the flow rate of superquadric and poly-superquadric elements decreases as the blockiness parameter increases. Geometrically asymmetric and elongated particles are rearranged to form interlocking and local clusters, which limit the relative motion between particles and reduce the flowability of non-spherical granular materials.