UC Berkeley

Contact detection and contact geometry are among the most important steps in Discrete Element Method (DEM) simulations. Accurately representing the contact between two particles is crucial, and when modeling fractured rock using polyhedral particles, the accuracy of the contact point calculation is essential for obtaining realistic and reliable simulation results. The point of contact is where contact forces are applied to particles in a DEM simulation and, thus, an inaccurate representation of that point leads to artificial torque acting on particles, resulting in non-physical rotation and particle interactions. Herein we present a new algorithm for accurately calculating the contact point between two colliding polyhedral particles. The algorithm uses the topology of the particles to assert their interaction with the plane of contact and not directly with each other. The new algorithm provides improved performance in terms of global stability of DEM models by mitigating numerically induced instability associated with errors and sporadic movement in the contact point calculation. The performance of the new algorithm is showcased in several examples that illustrate how accurately representing the contact point is a requirement for generating reliable numerical simulations.