Authors

Abstract

In order to determine the parameters of buckwheat grain required in discrete element method (DEM) simulation, this paper carried out experiments for the measurement and simulation of the repose angle of buckwheat grain based on the stacking test. Taking the obtained repose angle as the response value, the simulation parameters were calibrated by the response surface method. The static friction coefficient of buckwheat-buckwheat and that of buckwheat-steel are significant factors affecting the repose angle. Based on the results of the steepest ascent test and the central composite design, a quadratic polynomial model for the repose angle and the 2 significant parameters was established and optimized. By solving the modified regression equation, the optimal combination of parameters was obtained: buckwheat-buckwheat static friction coefficient of 0.482, buckwheat-steel static friction coefficient of 0.446. It was found that there was no significant difference between the results of the simulation test under the best combination and physical test (P > 0.05), indicating that the parameter calibration method based on the response surface method is feasible. The optimal combination of calibrated parameters can provide reference to the simulation of buckwheat production process by DEM and machineries design.

Abstract in Chinese

为了确定离散元模拟所需的荞麦籽粒参数，本文基于堆积试验进行了荞麦籽粒休止角的测量与模拟试验。以得到的休止为响应值，采用响应面法对仿真参数进行了标定。在Plackett-Berman试验中，荞麦-荞麦和荞麦-钢板的静摩擦系数是影响休止角的重要因素。根据最陡爬坡试验和中心组合设计的结果，建立了休止角和2个显著参数的二次多项式模型，并进行了优化。通过求解优化后的回归方程，得到最佳参数组合：荞麦-荞麦静摩擦系数为0.482，荞麦-钢静摩擦系数为0.446。在最佳组合下进行了验证实验。结果表明，验证试验结果与测量试验结果无显著性差异（P>0.05），说明基于响应面法的参数标定方法是可行的。标定参数的优化组合可为荞麦生产过程的离散元模拟仿真及机具设计提供参考。