| Lobster shell-inspired 3D-printed ISRU composite panel for micrometeoroid shielding applications on the lunar surface |
| Establishing a permanent human presence on the lunar surface is a tough challenge considering the harsh in-situ environmental conditions, among them micrometeoroids and small debris. In average, two meteoroids of one microgram hit each square meter of the lunar surface every year [1], at around 13 km.s-1 [2]. The significant amount of energy released during impact, as well as the random and unpredictable nature of such a risk, lead to consider the implementation of shielding over the critical installations.
On an ISRU perspective, lunar regolith arises as a promising raw material for many applications [3], of which that targeted here. The lab-scale production of fibres out of this material has been recently demonstrated [4]; nevertheless, basalt fibres also turn out to be a reasonable analogue, at a cheaper cost and available in greater amounts. The latter are embedded in a polyamide matrix, which is in fine the composite material used in this work.
Crustacean shells, such as the lobster carapace, were selected as a source of inspiration for efficient energy-absorbing panels, as they feature among the most tenacious natural structures ever reported [5][6]. The carapace is a functionally graded material in which porosity increases inwards. The understanding of the underlying energy dissipation mechanisms enables to propose bioinspired composite panels with tailored porosity.
Given the level of complexity required by such structures, additive manufacturing was selected, more precisely the continuous filament fabrication technology. It enables the production of composite materials with a large design freedom and enhanced mechanical strength, compared to the traditional fused filament fabrication process, by taking advantage of the filament anisotropy [7]. Turning the desired architecture into a tangible object requires the generation of a specific printing path, given the continuous nature of the filament.
References
[1] M.I. Allende and al.; Prediction of micrometeoroid damage to lunar construction materials using numerical modelling of hypervelocity impact events International Journal of Impact Engineering, 2020
[2] H.A. Zook; The state of meteoritic material on the Moon Proceedings of the 6th Lunar Science Conference, 1975
[3] Cesaretti and al.; Building components for an outpost on the Lunar soil by means of a novel 3D printing technology Acta Astronautica, 2014
[4] Panajotovic and al.; MoonFibre – Fibres from Lunar Regolith RWTH Aachen, 2019
[5] Ingrole and al.; Bioinspired energy absorbing material designs using additive manufacturing Journal of the Mechanical Behaviour of Biomedical Materials, 2021
[6] Lian and Wang; Microstructure and Mechanical Anisotropy of Crab Cancer Magister Exoskeletons 2014.
[7] Kabir and al.; A critical review on 3D printed continuous fibre-reinforced composites: history, mechanism, materials and properties 2020.
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