Development of a Mathematical Model and Structural Optimization of the Specific Resistance of a Broken Line Subsoiler

Saline-alkali soil has the characteristics of high density, high firmness and poor permeability. Aiming at the problems of shallow subsoiling depth, large subsoiling specific resistance and small soil bulkiness in subsoiling operation in saline-alkali soil, this paper establishes a mathematical model of the specific resistance of a broken line subsoiler and uses genetic algorithm and the discrete element method to optimize the structure design of the subsoiler. Firstly, the mathematical model was developed by analyzing the force of the subsoiler in the working process. The genetic algorithm was used to solve the problem, and three geometric models of the broken line subsoilers were fitted. Then, EDEM software was used to simulate this, and the tillage performance was evaluated with draft force, soil disturbance area, subsoiling specific resistance and soil bulkiness as the indexes and verified by field experiment. The results showed that the subsoiling specific resistance of the three broken line subsoilers was significantly lower than that of the standard subsoiler in the simulation test. Compared to the standard subsoiler, the soil disturbance area of the broken line subsoiler-B increased by 12%, the draft force decreased by 19%, the subsoiling specific resistance decreased by 26% and the bulkiness increased by 6%. The field experiment results showed that the broken line subsoiler-B reduced the traction force and improved the tillage efficiency compared to the standard subsoiler, which was consistent with the analysis results of EDEM. The broken line subsoiler can effectively enhance the quality of cultivated land.