Analysis of soil disturbance process by vibrating subsoiling based on DEM-MBD coupling algorithm

Current technology and measurement have posed a serious limitation on theoretical analysis of soil trough and field test in an active vibration subsoiler in recent years. This study aims to clarify the influence of complex vibration on topsoil disturbance using the discrete element method (DEM) and multi-body dynamics (MBD) coupling algorithm. The process of vibrating subsoiling was also simulated to delve into the behavior of soil disturbance under the complex vibration and motion. A simulation model was then established for the tractor-vibrating subsoiler-soil system. SolidWorks software was used to create the three-dimensional (3D) models with the simplified mechanical structure. The obtained 3D modes were imported into Adams platform to be constrained, driven, and simulated, according to the actual working conditions of the vibrating subsoiler. The vibration stability index was established for the whole simulation model of the tractor-vibrating subsoiler-soil system. The Edinburgh Elasto-Plastic Adhesion (EEPA) contact mechanics model was adopted to consider the viscosity, elasticity, and plasticity of soil particles, indicating an excellent simulation for most soils. The coupling simulation of EDEM and Adams was carried out to determine the coupling files and parameters using the Co-simulation program in Adams. The main object was focused on the disturbance behavior of the adjacent Omni-directional deep loosening shovel to the surrounding soil. The working process of the vibrating subsoiling machine was also simulated to evaluate the vibration and the disturbance effect, together with the frame structure of the Omni-directional deep loosening shovel on the soil. The results show that the soil disturbance interface was highly coincident with the theoretical trajectory of Omni-directional deep loosening shovel, and the cross-sectional soil disturbance in the forward direction was in the M-shaped ridge and V-shaped groove. The motion state of the simulation model was divided into the soil penetrating and the vibration subsoiling stroke, according to the real vibrating subsoiling. In the soil penetrating stroke, the Omni-directionaldeep loosening shovel formed a crescent disturbance area to the soil disturbance, when the vibration frequency f was 5 Hz and the forward velocity v was 0.56 m/s. In the vibration subsoiling stroke, the particle velocity showed three-color distributions: low speed 0-0.1 m/s, medium speed 0-0.3 m/s, and high speed 0.3-0.5 m/s. As such, the area near the shovel tip was divided into the transition, backfilling, and disturbance areas, each of which circulated regularly in the period. The soil disturbance in a vibration cycle was illustrated to intercept the trajectory and simulation images. It was found that the variation in the motion state of soil particles in each region, together with the regular changes during the period. The soil at different positions of the Omni-directional deep loosening shovel was cut from that along three directions in the spatial range. The disturbance of the Omni-directional deep loosening shovel to the soil was mainly concentrated in the interior of the frame structure. The range of disturbance depended on the maximum cross-sectional area of the Omni-directional deep loosening shovel, where the severe disturbance to the soil was around the solid structure of the frame shovel. Taking the soil bin soil as the material similar to the soil property in the discrete element model, a soil bin test was conducted to set the same working parameters as the simulation. It was found that the simulated profile of soil disturbance was basically consistent with the experiment. Correspondingly, a qualitative explanation can be made on the process of soil disturbance caused by Omni-directional deep loosening shovel in a vibrating subsoiling machine and the velocity distribution of soil particles. As such, the vibrating subsoiling operation of soil was simulated regularly in the actual field.