Modeling the interaction of soil and a vibrating subsoiler using the discrete element method

A vibrating subsoiler can effectively reduce the draft force compared to a rigid one. Several theoretical and experimental methods have been developed to study the interaction of soil and vibrating tools, enabling the exploration of the mechanism of a vibrating subsoiler to reduce the draft force. However, these methods are unable to predict the dynamic force of tools and soil behavior because of nonlinear soil properties. This paper employs the discrete element method (DEM) to simulate vibrating tillage. The aim is to clearly understand the dynamic force of vibrating tools and soil behavior. Three different types of representative vibrating subsoilers and one rigid one were selected for this study. These subsoilers varied in their tines and vibrating structures. The DEM model of soil and subsoilers was established. Results showed that the draft and vertical dynamic forces of the vibrating tines periodically changed and had distinct peak and valley phases in one period. The value of the draft and vertical forces in the valley phase of a vibrating subsoiler was much less than that of the rigid one, which led to the decrease of mean draft force. The soil disturbance widths, velocities, and horizontal and vertical forces of soil particles also periodically changed. Soil ruptures mainly occurred when a tine vibrated in the forward direction. Compared with a rigid tine, a vibrating tine had more time to disturb soil particles and thus to achieve better soil fracture. The DEM model was validated by comparing it with an actual soil bin test. The errors of the simulation model in predicting the soil disturbance and forces were less than 13.23% and 9.65%, respectively, indicating that the model is a useful tool to simulate the dynamic interaction of soil and a vibrating subsoiler.