Effect of gravity on the mechanical properties of lunar regolith tested using a low gravity simulation device

Abstract

Simulations of the bearing capacity and shear strength of regolith under Earth’s gravity produce different results from those under low gravity. A low-gravity simulation device was developed in this study, and an internal stress model of regolith simulant was established to correct the errors. The model revealed additional force on both shear plane in the shear test and the press plate area in the pressure–sinkage test. The sinkage and shear test results showed that low gravity decreased the deformable index n, frictional modulus kφ and cohesion c, whereas there were no obvious changes to the cohesive modulus kc and internal friction angle φ. The sinkage generally increased as the gravity decreased under a consistent normal load larger than 50N, but when the wheel load was lower than 50N, the sinkage of the TYII-1 simulant was larger under 1G than 1/6G. Gravity had little effect on the shear strength of the regolith. However, the tractive thrust of the TYII-1 simulant was lower under 1/6G than 1G. The smaller difference was due to differences in the way the soils responded to changes in the gravity level for the TYII-2 simulant.