DEM simulation of soil-tool interaction under extraterrestrial environmental effects

TL;DR

This study uses DEM simulations to analyze how lunar environmental factors like low gravity and vacuum affect soil-tool interactions, revealing increased resistance and energy needs for lunar excavation compared to Earth.

Contribution

It introduces a DEM simulation framework to evaluate soil-tool interactions under lunar environmental conditions, highlighting the significance of van der Waals forces and gravity effects.

Findings

Cutting resistance and energy consumption increase linearly with gravity.

Soil strength and forces significantly rise in lunar conditions.

Van der Waals forces notably impact excavation forces on the Moon.

Abstract

In contrast to terrestrial environment, the harsh lunar environment conditions include lower gravity acceleration, ultra-high vacuum and high (low) temperature in the daytime (night-time). This paper focuses on the effects of those mentioned features on soil cutting tests, a simplified excavation test, to reduce the risk of lunar excavation missions. Soil behavior and blade performance were analyzed under different environmental conditions. The results show that: (1) the cutting resistance and the energy consumption increase linearly with the gravity. The bending moment has a bigger increasing rate in low gravity fields due to a decreasing moment arm; (2) the cutting resistance,energy consumption and bending moment increase significantly because of the raised soil strength on the lunar environment, especially in low gravity fields. Under the lunar environment, the proportions of cutting resistance, bending moment and energy consumption due to the effect of the van der Waals forces are significant. Thus, they should be taken into consideration when planning excavations on the Moon. Therefore, considering that the maximum frictional force between the excavator and the lunar surface is proportional to the gravity acceleration, the same excavator that works efficiently on the Earth may not be able to work properly on the Moon.