Three-dimensional discrete element modeling of the irregularly shaped pebbles used in a truck escape ramp
The truck escape ramp is a clump of pebbles that is located alongside downgrades. As the pebbles are randomly placed in arrester beds, few studies have been conducted on simulation methods of the irregularly shaped pebbles. This paper proposed a pebble DEM model to analyze the micro-contact mechanism of the pebbles. Based on a polynomial algorithm, the 7th fit was selected and the coefficients of the edge curves were recorded. Second, the main view and left view were filled with preset numbers of ball elements. According to the ball element parameters, the ball elements were extended to three-dimensional models. Third, based on the edges of the main view and the top view, the ball element parameters were recalculated. Then, compression tests were conducted, and the key parameters of the pebble DEM model were calibrated. Based on the built pebble DEM model, compression tests were simulated with different pressing plate velocities and laying thicknesses. The results indicate that for increases in the pressing plate velocity, the contacting forces on the plate correspondingly increase, and this increase is linearly shaped. The results for different laying thicknesses indicate that for increases in the laying thickness, the contacting forces on the plate correspondingly decrease.
Keywords: Discrete element method (DEM), Irregularly shaped pebbles, Numerical modeling, Force chains, Pebble velocity