The role of bond and damping in the discrete element model of soil-sweep interaction

This paper introduces a discrete element method (DEM) model for studying soil-sweep interaction, where the investigated microscopic parameters were the viscous damping which was utilised for energy dissipation and parallel bonds for simulating the effect of moisture in the particle assembly. The aims were to improve the DEM model with the appropriate set of viscous damping to simulate the effect of the tool's working speed on draught and investigating the set of bond radius multiplier of the parallel bonds for modelling the soil's moisture content (mc) with the spherical particles used. For verification of the DEM model's input parameters, two laboratory soil bin studies were made. The first test confirmed that the draught forces were comparable with the viscous damping used, where the particle assemblies were overdamped at low speeds (0.5-2.8 m s−1) and underdamped at higher working speeds (2.8-4.1 m s−1). The second soil bin test proved that the appropriate set of parallel bonds enable the simulation of the soil volumetric moisture content over the range 2, 15, 30, 35%. The draught was lower in the simulation using radius multiplier of 0.0, 0.2 in the same manner as 2, 15% mc in the laboratory test. The draught was highest in the model at radius multiplier of 0.5, similarly to the 30% mc in the soil bin study. When the bond radius multiplier was set to 0.8, the DEM model able to simulate lower draught similarly to soil with 35% mc.