Abstract:In order to determine the optimal contact parameter combination of discrete element simulation of coated corn seeds, the error rates of repose angle and stacking angle of coated corn seeds obtained from the real test and simulation under different parameter combinations were used as response values to calibrate the discrete element simulation parameters of coated corn seeds. The classical mechanics theory was used to establish the kinetic equations of granular particles, and the main contact parameters were determined by the analytical mechanics equations. The Central Composite test was used to establish the multiple quadratic regression equation between the model parameters and the response values. The genetic algorithm NSCA-Ⅱ was used to optimize the multiple quadratic equation, and the verification test was carried out to obtain the optimal contact parameter combination of the coated corn seed discrete element model, that was the interspecies static friction coefficient was 0.432, the interspecies rolling friction coefficient was 0.082, and the interspecies collision recovery coefficient was 0.178. Combined with bench test and simulation test, through inclined plane sliding test, the static friction coefficient between horse tooth corn seed and plexiglass was 0.1164. In order to verify the accuracy of the calibration parameters, the four contact parameters were used to carry out the simulation test of seed ejection, the simulation test result of the stacking angle obtained by the test was 27.83°, compared with the actual values of seed dropping, the error was 1.76%, the results showed that the demarcated discrete element model and contact parameters of coated maize seeds were accurate and reliable, and could be used in discrete element simulation experiments.
