颗粒堆内微观力学结构的离散元模拟研究

将离散单元法应用到三维堆积过程的模拟计算，探讨了滑动摩擦及滚动摩擦对堆积形成的影响，得到了颗粒堆内部的应力分布规律，发现颗粒堆的形态是由滑动摩擦和滚动摩擦共同决定的，在堆内颗粒间的作用力基本呈树状结构.在模拟得到的颗粒堆中出现了应力分布奇异现象，在堆积角较大的情况下，颗粒堆与地面间作用力的最大值常发生在距堆底中心不远的环状区域，而并非发生在堆底的中心；在堆积角相对较小时颗粒堆与地面间作用力的最大值较容易发生在堆底的中心.对于一个颗粒堆，具体会发生哪种受力情况具有一定的偶然性.关键词：堆积离散单元法计算颗粒力学

Discrete element simulation of the microscopic mechanical structure in sandpile

The formation of three-dimensional sandpile was simulated by using discrete element model. The influence of sliding friction and rolling friction of particles on the formation of sandpile was discussed. The simulation results show that the angle of repose of sandpile is determined by both sliding friction and rolling friction. The trec-shaped microscopic mechanical structure in the sandpile was revealed by the simulation. The stress distribution at the bottom of sandpile was also obtained by the simulation. The simulation results show that when the angle of repose of sandpile is large, normal stress profiles with a clear stress dip near the center of the pile is generally formed, and when the angle of repose of sandpile is small, the maximal normal stress generally appears near the center of the pile. Which type of the stress distribution at the bottom of sandpile will emerge is rather accidental,depending on the real process of pileing.