Dynamic Response of Lunar Soil Caused by Landing Impact

Abstract

In recent years, there is an increasing interest on lunar exploration and future utilization of lunar resources. Technology of landing is a key in order to establish frequent access to the lunar surface. For a lunar lander, one of the major tasks is to accurately determine the loads and energy absorption capability during the landing event. On the other hands, it should be paid special attention on the study of wave propagation phenomenon in lunar soil and its dynamic response and dissipated energy by the lunar soil. A series of model tests for the simulated lunar soil model with plane and slope are conducted. The model tests are performed to study on the regularity of wave propagation and its attenuation in lunar soil. The waveform of acceleration, velocity and earth pressure in the model are observed. The research focuses on the analysis of the phenomenon through numerical methods. The wave propagation characteristics of the lunar soil model with plane and slope is assessed by means of dynamic FEM analyses in three dimensions. The analysis is obtained in the time domain and allows the consideration of multiple wave reflections between layers. It is concluded that the wave field propagation in lunar soil during landing impact mainly shows Rayleigh wave along axial of impact pads, and repeatedly superimposing occur between impact pads. The predominant frequency of the landing impact is over 100 Hz. The response is quickly attenuated in lunar soil and its propagation distance is very limited. Moreover, according to the numerical results and the model test results, it can be found that a small input wave velocity ( 0.05, and when input wave velocity is 4 m/s, the ground floor of the landing pad is in plastic.