Experimental study and DEM analysis on rigid driving wheel's performance for off-road vehicles moving on loose soil

An experimental and numerical investigation was carried out on the performance of a single-wheel travelling over various kinds of loose soil, including dry sand, wet sand, and mud. The experiments were conducted using a testbed equipped with a displacement transducer, a torque sensor, etc., to get the information on sinkage, driving torque, and drawbar pull. It was found that within certain water content, the trafficability of wet sand is better than that of the dry sand. On the other hand, the behaviour of a wheel when running over mud is very different comparing to the case of sand, for which the shear force tends to be negligible because of the near-flow property of the mud. It was also demonstrated that the cohesion of the mud can't be ignored since the mud will attach to the wheel so that the shear force is offered by the internal friction angle of mud rather than the friction between wheel and soil. In the numerical work, DEM (discrete element method) was used to simulate the interaction between wheel and sand, and the agreement with the experiments was fairly good.