Tangential force model study of lunar dust particles based on Hertz-Mindlin theory and sensor technology

In this paper, the existing Hertz-Mindlin model is modified and an improved tangential force model is introduced. Since the maximum static friction force is larger than the sliding friction force, it is unreasonable to assume that the friction force remains the same no matter if particle sliding occurs. Therefore, the static friction coefficient during sliding process in Hertz-Mindlin model is reassigned in the improved model and the tangential friction force is depicted by piecewise functions. Besides, discrete element analysis and simulations are carried out in EDEM to prove the rationality of the improved theoretical model. From the simulation results, it can be seen that tangential force under the improved model shows an obvious change when particle sliding occurs while tangential force under the existing Hertz-Mindlin model remains unchanged during the whole loading process, which means the improved friction model can simulate the particle sliding a lot more reasonable than the existing Hertz-Mindlin model.