Distinct element method for static and flow mobility characteristics of lunar regolith based on particle shape characteristics

Since it exhibits uniquely grain shape, physical and mechanical characteristics, the lunar regolith is extremely important for utilization of in-situ resources, selection of base station location and construction in lunar exploration. Based on the data of the shape characteristics of the lunar regolith, the distinct element method (DEM) is employed to study the static and flow mobility characteristics of the lunar regolith. Firstly, to reproduce the macroscopic static and flow behaviors of the lunar regolith sample, a complete three-dimensional contact model considering the grain shape characteristics of the Chang'E-5 mission is used, and then the corresponding shape parameters (coefficient of rolling resistance β) for different grain sizes are determined. Secondly, the triaxial tests under different confining pressures and the rotating drum tests under different rotating speeds are simulated using the DEM, and the samples include the lunar regolith, Toyoura sand, and glass beads. Finally, a contrastive analysis of the static and flow mobility characteristics of the three materials is conducted. The simulated results show that in the triaxial tests, compared with the other two materials, the lunar regolith has the largest apparent cohesion and internal friction angle, and it exhibits dilatancy in the shearing process. In the rotating drum tests, compared with the other two materials, the lunar regolith has the largest inclination angle and void ratio, and the smallest shearing rate and coordination number. Under a certain range of the inertia number, the lunar regolith has the largest effective friction coefficient compared with the other two materials, indicating that it has the smallest flow mobility.