Abstract:Existing development for chopping and throwing components in harvester of fodder rape crop, which employs discrete element simulation, has persistent challenges that use the accurate parameters to construct the right model, highlighting a need for calibration of model parameters. Taking the rape crop stalks in the bolting stage as research object, the parameters calibration of discrete element simulation model was carried out by using the EDEM simulation software. In the first step, the diameter, density, Poissons ratio and other mechanical and physical properties of the rape crop stalk were determined. Next, a cylindrical lifting physical test of the rape crop stalk particles was implemented. Simultaneously, a series of virtual simulation experiments on the particles pileup by using the Hertz-Mindlin basic model was carried out in EDEM. The arrangement of the experiments was followed the regular twolevel factorial design, the steepest ascent design and the response surface methodology, and the basic contact parameters of the stalk particle model, such as collision recovery coefficient, static friction coefficient, and rolling friction coefficient, were determined. Subsequently, a threepoint bending failure test of the rape crop stalk was implemented and a series of virtual simulation experiments on bending stalk using the Hertz-Mindlin with bonding contact model were carried out in EDEM. The response surface methodology was applied to determine the bonding parameters such as normal stiffness, tangential stiffness, normal stress and tangential stress of feed rape stalk particle model. Finally, simulation experiments were carried out using the obtained parameters, including the stalk particles accumulation test and the bending stalk test. Compared with the physical test results, the error between the simulation and the physical test value of the angle of repose was 2.27%; the error between the simulation and the physical test value of the bending broken force was less than 4.21%. The results showed that the calibration method was correct and the calibration model was accurate. The research provided basic parameters for the discrete element simulation analysis of mechanized harvesting process of fodder rape crop in bolting stage, and provided a method for parameters calibration of discrete element simulation model for chopping stalk crops.
