Shape memory polymer composite based thin shell structures for modular construction of deployable lunar habitats

Shape memory polymer composite based thin shell structures for modular construction of deployable lunar habitats

Recent global efforts to return to the moon have intensified research into lunar habitats, favouring deployable and rigid structures. Moreover, the durability in unexplored harsh environmental conditions and lower weight are the governing factors of materials for these structures. In this context, shape memory polymer-based composites (SMPCs) are ideal for these habitats because of their potential to create lightweight thin-shell structures and their proven ability to revert to their original shape when stimulated by external factors such as heat. Bisphenol-A Cyanate Ester (BACE) and Polyethylene Glycol (PEG) based shape memory polymers (SMPs) were identified as promising materials due to their high glass transition temperatures and stable thermomechanical properties. Combining BACE with PEG enhances mechanical and shape memory properties, allowing for tailorable thermomechanical properties. The synthesised SMP demonstrated stable thermomechanical properties at the highest lunar ambient temperature (125±2°C) and excellent shape programming at ~170°C. Combined with glass fibre layers and graphene nanoplatelets (GNP), it produced an SMPC with excellent quasi-isotropic properties for manufacturing thin-shell structural components. Adding GNP further enhanced thermal conductivity, increasing the shape recovery effect while acting as a barrier against Atomic Oxygen (AO). The developed SMPC was used to fabricate modular thin-shell hemispherical components. The fabricated components were assembled to demonstrate a hemispherical thin-shell section as a part of a hemispherical dish-end pressure vessel. The fabricated components experimentally showed mechanical integrity and shape memory behaviour, which agreed with their finite element models. The SMPC underwent a series of lunar and space environment-simulated durability tests that showed minimal effect on its mechanical, thermomechanical, and shape-memory properties. This highly durable SMPC is suitable for deployable rigid lunar habitats and space applications, reflecting numerous advancements in future space exploration.

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