Parameter calibration method for discrete element simulation of cut seed potato tubers

The shape of materials significantly affects their kinematic properties. In discrete element method (DEM) simulations, accurately modeling both the shape and mechanical properties of materials is essential. Thus, this paper proposes a modeling approach based on the number of cut surfaces on cut seed potato tubers. To develop accurate models, the intrinsic parameters of cut seed potato tubers with varying numbers of cut surfaces were measured. Drop tests, pendulum tests and inclined-plane tests were used to calibrate the coefficients of restitution, static friction and rolling friction for tuber-steel plate interactions, as well as the inter-tuber coefficient of restitution. A comprehensive approach combining Plackett-Burman design, the method of steepest ascent and Box-Behnken response surface methodology was used to calibrate the inter-tuber friction parameters, yielding static and rolling friction coefficients of 0.453 and 0.024, respectively. Validation with the pumping plate method showed a relative error of 1.27% between the simulated and measured angles of repose. In feeding tests using an electromagnetic vibrating hopper, the simulation results differed from the experimental results by less than 5%. These calibrated parameters provide a robust theoretical basis for designing and analyzing cut seed potato planting equipment.