摘要颗粒系统堆积的休止角是颗粒学中的一个重要的基础性的问题,目前尚缺乏对其影响因素和变化规律的认识。基于实验测量的研究受限于可用的颗粒种类和测量手段,难以完备地揭示各种物理参数对休止角的影响规律。离散元(Discrete element method, DEM)是一种可直接对复杂的大型颗粒系统的运动进行仿真计算的数值方法。本文借助 DEM 方法对颗粒系统的休止角问题开展了高精度数值研究,探索了可影响休止角的重要的颗粒物性参数。仿真结果表明,滑动和滚动摩擦系数均与休止角的大小呈正相关,滑动摩擦系数可将休止角提升一倍,而滚动摩擦系数对休止角的影响存在一个上限阈值,达到该阈值后将不能继续增加休止角的大小;颗粒的杨氏模量、回弹系数对休止角的影响较小。
Abstract:The angle of repose of granular accumulation is a fundamental issue in granulometry, and our current understanding of its influencing factors and variation patterns is still incomplete. Experimental research methods are limited by the existing types of granules and measurement means, making it difficult to comprehensively reveal the influence of individual physical parameters on the angle of repose. The Discrete Element Method (DEM) is a commonly used computer simulation method for studying granular systems, allowing for direct modeling and calculation of the transient behavior of complex large-scale granular systems. In this paper, the DEM method was used to conduct a systematic numerical study on the angle of repose of granular accumulation, exploring the important granular physical parameters that can affect the angle of repose. Simulation results show that both sliding and rolling friction coefficients are positively correlated with the size of the angle of repose. The sliding friction coefficient can double the angle of repose, while the influence of the rolling friction coefficient on the angle of repose has an upper threshold value. Once this threshold is reached, it will no longer increase the size of the angle of repose; the effects of Young's modulus and the coefficient of restitution on the angle of repose are relatively minor.