Parameter calibration of discrete element simulation model for Panax notoginseng planting soil

Objective To obtain the parameters of the discrete element simulation model for the interaction between Panax notoginseng planting soil and soil-engaging components.

Method This paper established a discrete element model of P. notoginseng planting soil based on the Hertz-Mindlin with JKR contact model, and calibrated parameters. Firstly, the JKR surface energy, restitution coefficient, static friction coefficient and rolling friction coefficient between soil particles and soil-65Mn steel plate were used as experiments factors, and the soil repose angle and the rolling distance of soil on the 65Mn plate were used as evaluation indexes. Secondly, the regression model for soil repose angle and rolling distance was established through the response surface optimization method based on Box-Behnken.

Result The regression model was optimized, and the optimal values of JKR surface energy, restitution coefficient, static friction coefficient and rolling friction coefficient between soil particles calibrated by simulation were 14.88 J/m², 0.53, 0.46 and 0.150, respectively. The calibrated optimal values of JKR surface energy, restitution coefficient, static friction coefficient and rolling friction coefficient between soil-65Mn steel plate were 7.02 J/m², 0.59, 0.57 and 0.058, respectively. Through the comparative analysis of the simulation test and the soil-bin test, the relative errors of the simulated and measured average resistance of the excavating shovel in the X and Y axis directions were 9.91% and 8.78%, respectively.

Conclusion The calibrated discrete element soil model parameters have high accuracy, and the research can provide a theoretical reference for the optimization of the soil-engaging components and equipment of the P. notoginseng harvester.