CALIBRATION AND TESTING OF SIMULATION PARAMETERS FOR RAPESEED BLANKET SEEDLING SHEETS BASED ON DISCRETE ELEMENT METHOD

It is difficult to accurately calculate the mutual force and seedling loss law between seedling needles and seedlings when conducting simulation analysis of cutting and transplanting rapeseed blanket seedlings with a transplanting machine due to a lack of reliable discrete element simulation parameters for rapeseed blanket seedlings. The physical and contact parameters of rapeseed blanket seedlings are calibrated in this study using the EDEM discrete element method. The Hertz Mindlin with JKR model in EDEM software was used to simulate the shear force of rapeseed blanket seedlings after conducting experiments to determine the density, shear modulus, Poisson's ratio, friction coefficient, and collision recovery coefficient between seedlings and steel materials. The surface energy parameters, recovery coefficient, static friction coefficient, and rolling friction coefficient between seedlings were used as experimental variables, with the maximum shear force of seedlings serving as the response value. Using Box Behnken's response surface optimization method, multiple regression fitting analysis was performed on the experimental results to obtain the regression model of seedling shear force, which was then optimized to obtain the parameter optimization solution for rapeseed blanket seedlings. Finally, the collision recovery coefficient was calculated to be 0.6. The ideal contact characteristics for seedlings are a static friction coefficient of 0.8, a rolling friction coefficient of 0.3, and a JRK surface energy of 12.3 J/m2.