月壤水平推剪试验的离散元数值分析

DEM Analyses of Horizontal Pushing Test on Lunar Ground

在未来的探月计划中,将进行月球基地的建设和月球资源的开发等活动,这些活动均涉及月壤开挖/开采问题,因此有必要研究月壤与设备间的相互作用。将月壤-设备相互作用简化为平板水平推剪过程,采用离散单元法模拟这一过程。考虑到月壤的颗粒形态及月球表面特殊的环境,将粒间抗转动作用和范德华力引入月壤微观接触模型,通过双轴压缩试验得到数值试样的强度指标。分别考虑月面环境、不考虑范德华力的月面环境、地面环境,对比分析了重力场和范德华力对水平推剪阻力、破坏面和能量消耗的影响。结果表明:随重力场增大,水平推剪阻力和能量消耗增加但不与重力场成正比,破坏面由圆弧面变为平直面;范德华力对水平推剪阻力和能量消耗影响很小,但使破坏面延伸范围更大。

In the future lunar exploration,soil excavation is essential for the construction of permanent lunar outpost and usage of lunar resources. It is necessary to investigate the mechanism of the interaction between lunar soil and excavation machines. DEM was used to simulate the horizontal pushing test which was a simplified machine-lunar soil interaction problem. Rolling resistance and Van der Waals forces between lunar soil particles were taken into consideration in the new lunar soil contact model to account for the effects of particle shape and lunar environment. With this model,the strength parameters were obtained with biaxial compression test,and the simulation of horizontal pushing test on lunar environment,lunar environment without Van der Waals forces and earth environment were performed. The effects of gravity and Van der Waals forces on pushing resistance,slip surface and energy consumption were analyzed. The results show that the pushing resistance and energy consumption increase with the gravity but are not in proportion to it. As gravity increases,the slip surface evolves from a curved one into a straight one. The Van der Waals forces have a little effect on the pushing resistance and energy consumption,but make the slip surface larger.