Research in mechanical model of bionic foot intruding into sands with different physical characteristics

Abstract In this study, a bionic foot with sand fixation and fluidization limitation functions was designed. Also a rectangular foot with the same sizes, named the common foot, was designed for comparison. Three kinds of quartz sands were selected to study how particle size, shape and compactness affected the intrusion performances of mechanical feet. The intrusion resistive forces and pressures of the bionic foot on these three kinds of quartz sands were all smaller compared with the common foot. Discrete element simulations showed particle disturbance areas were smaller and particle motion trends were more consistent under the bionic foot versus the common foot. The intrusion resistive forces of these two kinds of mechanical feet firstly increased and then decreased with the increasing particle sizes of quartz sands. Moreover, the intrusion resistive force on spherical particles was less than that of irregular particles for both the bionic foot and the common foot. The corresponding resistive forces of mechanical feet were characterized based on quartz sand compactness. The classic pressure-sinkage model was modified based on the intrusion tests, and the relationships between intrusion resistive force and mechanical foot depth were obtained.