Discrete element modeling and experimental research on the shear properties of corn stubble

Abstract

ABSTRACT Under the conservation tillage model, corn stubble with a complex structure has become the main obstacle for the operation of tillage tools. To better design relevant tillage tools as a reference, this study established a discrete element model of corn stubble. The intrinsic parameters and partial contact parameters of corn single root (CSR) were obtained through physical experiments, and the maximum shear force (Fmax) of CSR was tested. Fmax was used as the response value, Plackett-Burman test, steepest climbing test, and Box-Behnken test were used to determine the optimal parameters of the discrete element model. The results showed that the coefficient of friction of CSR-CSR, the coefficient of friction of CSR-steel, and the bonded disk radius all had significant effects on Fmax (P<0.01). The optimal solution is when they are 0.81, 0.76, and 0.93 mm respectively. Under this condition, the relative error of Fmax between the simulation and the fitting equation was 2.85%. In addition, shear validation tests were conducted on CSR with different diameters. Finally, based on the actual size of the corn stubble, a discrete element model of the entire corn stubble was established, which can provide a reference for studying the crushing of corn stubble.

Keywords

• corn stubble
• shear test
• DEM
• parameter calibration
• simulation