DEM model acquisition of the corn ear with bonded particle model and its simulated parameters calibration.

The corn variety “Zhenghong 507”, which is widely cultivated in hilly and mountainous areas of Southwest China, was assigned as the research object. The discrete element model of the mid-section of the corn ear that can be threshed was established by integrating the Hertz-Mindlin with the bonding V2 contact model, and the crucial bonding parameters were simulated and calibrated. With the measured normal threshing force (6.34 N) and tangential threshing force (4.75 N) of a single kernel as target values, the parameters of bonding characteristics between the kernel and the cob of corn ear were screened and optimized for significance via the Placket-Burman test, steepest ascent test, and the central composite design. The results indicate that the optimal parameter combinations for the normal stiffness and shear stiffness per unit area, normal strength, shear strength, contact radius between kernels, contact radius between cobs, and bonded disk scale were 3.4 × 108 N·m−3, 2.238 × 108 N·m−3, 0.6 × 106 Pa, 0.364 × 106 Pa, 1.87 mm, 16.5 mm and 1.321. Finally, the accuracy of the corn ear DEM model was validated by comparing the simulation to the physical test using the threshing rate as an evaluation index combined with the quality distribution of kernels after threshing. [ABSTRACT FROM AUTHOR]