Structural efficiency of varying-thickness regolith-based lunar arches against inertial loading

Abstract

Following the current trend towards the lunar exploration and habitation, this study focuses on the development of efficient arch forms to be adopted for future long-span shielding structures on the lunar surface. More specifically, the static behaviour of the optimised, varying-thickness arches (VTAs), produced by a previously proposed iterative form-finding algorithm based on limit thrust-line analysis under gravitational and seismic loading is examined herein. These form-found arches are assumed to be constructed by laser-sintered additive manufactured lunar regolith. This paper starts with the visualisation of the limit thrust line using finite element analysis (FEA) on constant-thickness arches (CTAs). Subsequently, it presents the results from FEA on both VTAs and CTAs where it is observed that the original VTAs need to be geometrically enhanced, by thickening certain weak areas of their cross-section in order to minimise the local principal stresses and strain energy. The work proceeds with the quantification of the efficiency of the enhanced VTAs against their CTA counterparts, in both terrestrial and lunar gravitational environments. The most efficient enhanced VTAs are selected and recognised as the best structural forms for either terrestrial or lunar applications among all the arches examined in this research. Eventually, the real capacity of those most efficient arches against lateral loading is attested by means of pushover analysis. As expected, it is found that the geometric enhancement has significantly increased their structural capacity.