Bond and fracture model in dilated polyhedral DEM and its application to simulate breakage of brittle materials

摘要

A bond and fracture model is developed to simulate the fracture and fragmentation with an explicit algorithm in the dilated polyhedral discrete element method in this paper. The Hertzian model is adopted in the contact model between the dilated polyhedral elements which is generated with the Minkowski sum theory. In the bond model, the bond points are initialized on the corresponding bond face of the interface between elements. The strain between two bonded points is calculated by the division of the distance of these two bonded points and the characteristic length, and thus the stress can be determined according to the elastic matrix. The bond force on each bond point is evaluated by stress and average area that every bond point represents on the bond face. The dynamic relaxation approach is employed to establish an explicit integration algorithm. A hybrid fracture model, considering the fracture energy and the unified damage, is developed to detect the fracture of the bond point. In the simulation of Brazilian test, parameters in the fracture model are analyzed to study the sensibility of this model. Furthermore, the ice load on the slope is simulated and validated with the ISO standard.