Local particle refinement in terramechanical simulations

TL;DR

This paper introduces a local particle refinement technique in DEM simulations that significantly reduces computational costs while preserving key mechanical properties, enabling more efficient terramechanical modeling.

Contribution

It presents a novel local particle refinement method that balances accuracy and efficiency in DEM simulations of granular soils, with systematic validation and performance analysis.

Findings

Particle count reduced by up to 25 times

Simulation time decreased by up to 43 times

Normalized errors remained below 11%

Abstract

The discrete element method (DEM) is a powerful tool for simulating granular soils, but its high computational demand often results in extended simulation times. While the effect of particle size has been extensively studied, the potential benefits of spatially scaling particle sizes are less explored. We systematically investigate a local particle refinement method's impact on reducing computational effort while maintaining accuracy. We first conduct triaxial tests to verify that bulk mechanical properties are preserved under local particle refinement. Then, we perform pressure-sinkage and shear-displacement tests, comparing our method to control simulations with homogeneous particle size. We evaluate $36$ different DEM beds with varying aggressiveness in particle refinement. Our results show that this approach, depending on refinement aggressiveness, can significantly reduce particle count by $2.3$ to $25$ times and simulation times by $3.1$ to $43$ times, with normalized errors ranging from $3.4$\% to $11$\% compared to high-resolution reference simulations. The approach maintains a high resolution at the soil surface, where interaction is high, while allowing larger particles below the surface. The results demonstrate that substantial computational savings can be achieved without significantly compromising simulation accuracy. This method can enhance the efficiency of DEM simulations in terramechanics applications.