凹形多面体离散单元的水平集函数接触算法

The polyhedral model can theoretically be used to construct arbitrarily shaped particles in the discrete element method (DEM).Due to the limitations of the DEM contact algorithm, the polyhedral model is only used to simulate the dynamic properties of particles with convex morphology.For polyhedral elements with concave surfaces, the contact algorithm for individual contact points can not accurately calculate the forces between elements.To accurately calculate single or multiple contact points between polyhedral particles, a level-set contact algorithm is developed for convex and concave polyhedral elements.In this method, the spatial level-set function and zero level-set function of the polyhedral element are established by the point-triangle element distance calculation method and the odd-even judgment method, and single or multiple contact points between polyhedral elements are obtained by solving the two level-set functions.To examine the reliability of the level-set contact algorithm, the packing and collapse processes of spherical and concave polyhedral granular materials are simulated using the DEM.Meanwhile, the effects of particles shapes on the volume fraction and angle of repose are analyzed.