Analysis and experiment of the bionic drag reduction characteristics of potato digging shovels on clayey black soil conditions

Digging resistance can dominate the energy consumption of potato-digging shovels in clayey black soil areas. In this study, a drag-reducing potato-digging shovel was designed using a bionic ripple structure. Among them, the rhizoma imperatae membranous sheath was taken as a bionic prototype. The optimal parameters were also determined for the drag reduction performance using the discrete element method (DEM) and soil trench test. The drag reduction and digging performance of the bionic digging shovel were then verified by the field test with the indexes of fuel consumption per unit time and drag force. The longitudinal arrangement was optimized for the better performance of the bionic digging shovel. Specifically, the optimal parameters of the bionic digging were A=2.5 mm, ω=0.5 in the soil trench test. The results show that the ripple shovel (y=2.5cos(0.5x)) achieved excellent properties of drag reduction at the soil moisture content under the condition of 35%, where the ordinary flat shovel drag reduction rate increased by 12.69%. In the soil moisture content of 65%, the spraying coating viscosity ripple shovel (y=2.5cos(0.5x)) still showed excellent properties of drag reduction, whereas the drag reduction rate of ordinary flat shovel increased by 18.27%. A comparison test was carried out between the ordinary flat and the bionic longitudinal ripple shovel. The drag-reduction rate of the bionic longitudinal corrugated shovel increased by 14.45%, and the fuel consumption rate was reduced by 17.15%. Bionic shovels presented better accumulation in the soil on the surface of the shovel rather than that in the shovel in the process of the mining operation. The bionic structure reduced the contact area and time between the soil on the surface of the shovel. The bionic shovel was performed on the short stagnation of the clod time under driving force in the same circumstances. The mining operation time of the shovel body was reduced to realize the energy-saving drag reduction in the same trip. The surface tension of the soil was also reduced using a bionic shovel surface with a low surface energy coating. The adhesion force of soil per unit area greatly contributed to the shovel of soil adhesion. There was a great decrease in the static friction coefficient between the shovel and the soil plane. Soil retention or accumulation was reduced for the soil conditions of movement and space on the surface of the shovel. Therefore, the bionic longitudinal ripple shovel performed better drag reduction, indicating the reasonable design of the bionic structure. The bionic structure of soil touching parts is of great significance in the application of potato harvesting and digging operations under clay and heavy black soil. The findings can lay a sound foundation for the energy saving and consumption reduction of the whole machine.