PARAMETER CALIBRATION AND DISCRETE ELEMENT MODEL OF HIGHLAND BARLEY STEM BASED ON EDEM

In view of the lack of accurate contact parameters and the difficulty of measuring contact parameters in the discrete element simulation of mechanized harvesting of highland barley, this study took the wax-ripening highland barley as the object, carried out the discrete element simulation of highland barley stem based on EDEM, and calibrated the discrete element simulation parameters of highland barley stem by response surface optimization. In this paper, Plackett-Burman test was used to screen 8 initial parameters. It was found that the static friction coefficient between highland barley stems, the rolling friction coefficient between highland barley stems, and the rolling friction coefficient between highland barley stems and steel plates have significant effects on the particle angle of repose. Based on the optimal value range of significant factors determined by the steepest ascent test, a second-order regression model of the angle of repose and significant parameters was established and optimized based on the results of Box-Behnken test. The optimal parameter combination of significant parameters was obtained as follows: static friction coefficient between highland barley stems is 0.27, rolling friction coefficient between highland barley stems is 0.07, and rolling friction coefficient between highland barley stems and steel is 0.26. Finally, the simulation results under the optimal parameter combination are compared with the actual test angle of repose. The relative error is 0.52 %. That indicates that the parameters of the simulation calibration are credible, which can provide a reference for the future research on the cleaning device in the mechanized harvesting of highland barley.