Numerical Simulation of the Emergency Brake Process in Granular Material Transportation Using DEM: Effect of the Liquid Bridge

Abstract

A numerical simulation of the emergency brake process in granular material transportation was carried out using the Discrete Element Method (DEM). The interaction laws between the particles were based on the contact mechanics in which the normal force was calculated by the Hertz contact law and the incremental tangential force was evaluated by the Mindlin-Deresiewicz theory. Moreover, the liquid bridge force was considered in the wet particle simulation and the effect was especially discussed. Two strategies including the spatial segmentation and reconstruction of orthogonal grids were introduced to analyze the interaction force on the truck during the braking and backfilling processes. It is found that the particles concentrated in front of the truck in the brake process with a slope forming on the upper surface of the agglomerating particles. The liquid bridge force can significantly influence on the particle and force distribution trends. When the liquid bridge force was considered, the particles moved more slowly, the slope was gentler and the force on both the bottom and front wall of the truck was higher. The findings in this study reveal that the liquid bridge force plays an important role on the instantaneous distribution of the particles and pressure on the truck walls and thus cannot be ignored in the simulation.