Discrete Element Modeling to Evaluate the Effects of Porosity on Regolith Responses during Cone Penetration Process

The human exploration of the Moon will require the knowledge of physical and mechanical properties of the regolith on the Moon's surface through terrestrial geotechnical testing methods such as cone penetration tests. This paper presents a study to investigate the effects of the porosity of lunar regolith simulants of JSC-1A on the interaction between regolith and cone penetrometer using the three-dimensional discrete element modeling (DEM). The particles of lunar regolith simulants are modeled using clumps in DEM with contact parameters calibrated to replicate the realistic stress-strain behavior of regolith simulants using triaxial tests. An assessment of the tip resistance and sleeve friction in relation to depth increase during the penetration into the lunar regolith is evaluated. The discrete element models with different regolith porosity settings are employed to develop a correlation between the porosity and the corresponding tip resistance and sleeve friction during the cone penetration process. The results from this study can provide useful references to assess the in situ porosity of lunar regolith on the Moon's surface based on the tip resistance and sleeve friction during the cone penetration process.