Calibration of Discrete Element Parameter of Rice Stubble Straw Based on EDEM.

In order to improve the accuracy of the parameters during the process of rice straw shredding and returning to the field in discrete element simulation, the stubble straw in the field after rice harvest were taken as the research object, and the contact parameters between straw and steel, straw and straw were measured through the slope test. Then based on simulation model and through the stacking angle and shear test, the bonding radius between straw model particles, tangential critical stress, normal critical stress, coefficient of restitution, static friction coefficient and dynamic friction coefficient were taken as the test factors, taking the shear resistance and radial stacking angle of straw as evaluation indicators, a multi-objective optimization simulation calibration experiment were conducted using the Box-Behnken experimental scheme. The results showed that the bonding radius between straw particles was 1.06 mm, and the normal critical stress of straw was 4.77x10¹⁰ Pa, tangential critical stress was 4.67x10⁶ Pa, the collision restitution coefficient between straw and straw was 0.21, the static Friction coefficient was 0.19, and the rolling friction coefficient was 0.09. The results of the simulation test results under the optimal parameter combination conditions and the physical test showed that the relative errors of the shear resistance and radial stacking angle of straw in the simulation test and physical test were 1.7% and 2.8%, respectively. This study could provide reference for the discrete element simulation analysis between straw and straw, as well as between straw and agricultural machinery. [ABSTRACT FROM AUTHOR]