A fast algorithm for the discrete element method by contact force prediction

The discrete element method (DEM) takes enormous calculation time because it requires a very small time step, one small enough to represent the large frequency in the contact dynamic model. In general, the equations of motion of particles are solved using the second-order Adams-Bashforth method, which estimates the values of contact force in the following calculation time by linear extrapolation, or by multi-step methods such as the predictor-corrector method. Inspired by these two conventional methods, we propose a Contact Force Prediction Method that makes a larger time step possible. Our method uses the predicted values of contact force at every contact point, which are exact solutions or numerical solutions of differential equations that represent two particle contacts. It has been confirmed experimentally that the proposed method gives reasonable results of packing and discharge simulations, and accelerates DEM calculation 3-8 times.