Discrete Element Analysis of the Reconstruction Method for Randomly Shaped Pebbles

Abstract

The pebble shape is a critical factor that affects the bearing characteristics of truck escape ramps. In this paper, a reconstruction method was proposed for randomly shaped pebbles used in truck escape ramps, and statistical analysis was conducted on the results of pebble compression tests. First, 100 pebble samples were randomly selected, and the pebble outlines were fitted in three views. The overlapping method was implemented to fill the three views with ball elements, and the ball elements were then extended into three-dimensions. The results demonstrated that the proposed method satisfactorily monitored the real pebble shapes. Second, statistical analyses were conducted on the parameters of the outlines, and corresponding data sets were built. The key parameters of the pebble DEM model, such as the friction coefficient, were calibrated based on the compression test results, and repeated simulation results verified the feasibility of the proposed pebble DEM model. Next, statistical analysis was conducted on the probability distribution of the contact forces. Third, simulations were conducted with different pressing plate velocities and pebble shapes. The results indicated that the pressing plate velocities had minor effects on the contact forces. As the pressing plate velocity increased, the slope of the contact forces correspondingly increased. The particle shape was a critical factor affecting the simulation results. With the same contact parameters, the simulation results of different pebble shapes varied greatly, which further indicated the importance of the proposed pebble shape reconstruction method. The proposed pebble DEM model could be further used in the design of truck escape ramps. INDEX TERMS Truck escape ramp, randomly shaped pebbles, discrete element method (DEM), contact mechanism, friction coefficient.

Analysis of the Load-Bearing Capacity of Pebble Aggregates

“…Considering the predominantly rigid nature of the pebbles, this study adopts the 'Linear Model' [24] as the fundamental DEM contact model for analysing pebble interactions. The key parameters of the pebble DEM model, particularly the friction parameter, are determined through open-top box compression tests, as detailed in [25]. The testing and simulation procedures are illustrated in Figure 7.…”

“…The key parameters of the pebble DEM model, particularly the friction parameter, are determined through open-top box compression tests, as detailed in [25]. The testing and simulation procedures are illustrated in Figure 7.…”

Investigating the Influence of Varied Particle Sizes on the Load-Bearing Properties of Arrester Bed Aggregates

“…This method utilises a discrete representation of particles on a homogeneous grid, diverging from traditional methods that approximate particle shapes using simple analytical equations or their combinations. Liu [15] developed a numerical reconstruction method for depicting irregular 3D particle structures. This approach significantly increases the efficiency of reconstruction and improves the accuracy of shape representation.…”

Influence of Aggregate Pollution in Truck Escape Ramps on Stopping Distance of Uncontrolled Vehicles

“…The discrete element method has since been widely used in the study of tire-soil mechanics [6][7][8] and truck escape ramps [9,10]. Nishiyama et al combined the finite element method with the discrete element method [11][12][13], using joint simulation to study the wheel-soil problem. In the simulation process, Nishiyama only activated the discrete element particles in a small range near the wheel, so that the activation area changed with the position of the wheel.…”