颗粒离散元模拟中的阻尼系数标定

Calibration of damping coefficient in discrete element method simulation

离散元模型中所采用的阻尼系数是不确定的,经常凭主观经验设定.为了使得物理模型与现实中的颗粒动力学属性符合更好,通过采用声频采样技术对物理模型中的阻尼系数进行标定,得出与实验符合的阻尼系数应为0.5左右.利用标定后的阻尼系数模拟了一元颗粒在圆柱形容器里的随机堆积过程,得到最终的堆积密度为0.625,与经典的实验结果一致.研究证明,在得到模型阻尼系数的同时,也确认了数值模型的正确性和用声频采样技术进行高精度碰撞时间检测的可行性.

In the discrete element method, the damping coefficient, which is a key parameter for rational simulation, is uncertain and often chosen based on researcher＇s experience. To make the physical model reflect the reality better, in this paper acoustic technology is used to calibrate the damping coefficient. Oscillogram of the acoustic wave generated by the collisions is analyzed and the calibrated damping coefficient is obtained to be 0.5. The calibrated parameters are used to simulate the random packing process of 2000 monosize spherical particles. The final packing density is 0. 625, which is in accordance with the classic measurements quite well. Besides the obtained correct damping coefficient, in this paper both the usefulness of the physical model and the practicability of acoustic technology for detecting the collision time are also demonstrated precisely.