A GENERAL MODELLING APPROACH FOR COATED COTTON-SEEDS BASED ON THE DISCRETE ELEMENT METHOD

In the current paper, a coated cotton-seed discrete element model was established. Furthermore, we designed a device for the simultaneous determination of the repose and accumulation angles, and Plackett-Burman and central composite design (CCD) tests were performed with the repose and accumulation angles as the test indexes. The static friction coefficient between seeds (SFCC) and the dynamic friction coefficient between seeds (DFCC) were observed to have a significant influence on the indexes and were thus selected for the subsequent analysis (P < 0.05). Analysis of variance revealed the terms of these two parameters to have a significant effect on the relative error of the repose angle (RERA) and the relative error of accumulation angles (REAA) (P < 0.05). A solution to the proposed mathematical model was determined via the NSGA- d genetic algorithm and the Pareto optimal solution set was obtained. Based on multi-objective optimization, the SFCC and DFCC were determined as 0.174 and 0.068, for RERA and REAA values of 1.715% and 1.712%, respectively. Simulations were then performed using the optimal parameters. Results of the T-test demonstrated that there were no significant differences between the simulated and physical test results.