Authors

Abstract

To improve the accuracy of contact parameters in discrete element simulations of seed metering devices and avoid errors arising during parameter measurement, this paper does not determine the values of each parameter in advance during parameter calibration. Instead, it directly uses the sliding friction angle, angle of repose, and rebound height as indicators, and employs regression analysis to calibrate the static friction coefficient, rolling friction coefficient, and restitution coefficient. The accuracy of the simulation parameters is verified through comparative experiments with the seed metering device. The results show that: 1) the static friction coefficient is proportional to the sliding friction angle, and the correlation between the two is independent of material properties. The calibrated static friction coefficients between seeds, PMMA, and PLA are 0.39, 0.43, and 0.54, respectively; 2) the rolling friction coefficient of seeds is exponentially related to the angle of repose, and the rolling friction coefficient between seeds is 0.030; 3) the restitution coefficient is quadratically related to the rebound height in drop tests, and the calibrated restitution coefficients of seeds with PMMA and PLA are 0.33 and 0.32, respectively; 4) the verification experiments demonstrate that the motion patterns of seed populations in simulation and physical experiments are similar, and the differences in seed filling rates between the two are not significant, proving the reliability of the calibrated simulation parameters.

Abstract in Chinese

为提高排种器离散元仿真接触参数的准确性，避免参数测定过程中产生的误差，本文在参数标定时不提前测定各参数的值，直接以滑动摩擦角、休止角和反弹高度为指标，利用回归分析方法，对静摩擦系数、滚动摩擦系数和恢复系数进行标定，并利用排种器的对比试验对仿真参数的准确性进行验证，结果表明：1) 静摩擦系数与滑动摩擦角成正比，二者间的相关规律与材料性质无关，标定得到种子与种子、PMMA、PLA间的静摩擦系数分别为0.39、0.43、0.54；2）种子的滚动摩擦系数与休止角成幂指数关系，种子间的滚动摩擦系数为0.030；3）恢复系数与跌落实验的反弹高度成二次函数关系，标定后的种子与PMMA和PLA的恢复系数分别为0.33、0.32; 4)验证试验表明，仿真试验与物理试验中种群的运动规律相似，二者的充种率差异不显著，证明标定后的仿真参数可靠。