Local particle refinement in terramechanical simulations

<b>Supplementary material:</b>This upload is meant as supplementary material to the article "Local particle refinement in terramechanical simulations" (Local particle refinement in terramechanical simulations). It contains scripts to run both bed generation and track tests, as well as data from 200 already run simulations.<br><b>Abstract</b>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.<br>

<b>补充材料：</b>本次上传为论文《土力学模拟中的局部颗粒优化》（Local particle refinement in terramechanical simulations）的配套补充材料，包含用于床层生成与轨迹测试的脚本，以及200组已完成模拟的实验数据。<br><b>摘要：</b>离散元法（Discrete Element Method，DEM）是模拟散粒土壤的强有力工具，但其较高的计算需求往往会导致模拟时长显著延长。尽管学界已对颗粒尺寸的影响开展了广泛研究，但针对空间尺度化颗粒尺寸的潜在收益却鲜有探索。本文系统探究了局部颗粒优化方法在降低计算开销的同时维持模拟精度的效果。首先通过三轴试验验证了局部颗粒优化下土体整体力学性能得以保留；随后开展了压入试验与剪切位移试验，将本方法与采用均匀颗粒尺寸的对照模拟进行对比。我们共评估了36组颗粒优化强度各异的离散元床层。结果表明，根据优化强度的不同，该方法可将颗粒数量大幅缩减2.3至25倍，模拟时长降低3.1至43倍，相较于高分辨率参考模拟的归一化误差介于3.4%至11%之间。该方法在相互作用较强的土壤表面保留了高分辨率，而允许地表下方使用更大尺寸的颗粒。研究结果证明，该方法可在不显著牺牲模拟精度的前提下实现可观的计算成本节约，能够提升土力学应用场景中离散元模拟的效率。