Designing for the Future: Optimising the structural form of regolith-based monolithic vaults in low-gravity conditions

该项目将研究整体土坯结构在低重力条件下的行为，得出支持未来空间探索的最佳结构设计框架。这种结构将起到屏蔽的作用，以保护关键资产(如机器人、燃料箱和发电站)和未来的充气结构(如生活区)免受外星环境中极端条件(辐射、沙尘暴、温度波动)的影响。线性和非线性数值结构模型以及参数静态和动态分析将确定利用本土材料生产此类结构的最佳设计方法，以最大限度地减少未来载人探索的重量负担。分析工作将通过实验离心机测试来验证，该测试可以在原型规模模拟低重力条件。这将是利用为地球制定的方法和概念进行可持续地外结构设计的第一个系统办法。到目前为止，考虑到在这种极端环境中需要解决的挑战，关于概念化外星结构的研究一直是孤立的，但对于如何实现这些结构还没有一个系统的方法。鉴于最近和正在进行的关于风化层模拟物的力学性质的研究、拟议的原位资源利用(ISRU)框架以及用于外星建筑的3D打印的进展，现在是时候将这些领域与为地球制定的结构设计战略结合起来，以确定受外星动态环境作用影响的低重力条件下使用的最佳结构形式。实现这一点的第一步是静态方法，并从广泛的整体式拱顶中识别出最适合低重力环境下的大跨度结构的拱顶。下一步将是确定与月球和火星强烈地面运动(浅层和深层月球地震、大地震(如果洞察飞行任务有的话)以及陨石撞击产生的地面运动)有关的地外自然灾害的工程需求参数。随后，将采用数值模型模拟不同的结构动力配置(包括土-结构相互作用、摇摆和隔震)，以使用确定的工程需求参数进行广泛的线性和非线性动力分析。这将导致对每种不同模型的动态性能进行评估，从而得出最佳结构选择。然而，一个关键的部分是在相同的外星激励下通过离心机试验来验证本项目中使用的数值模型。然而，研究风化石基结构材料的性能不在本项目的范围之内，因为风化石质模拟材料将用于该项目的实验部分。该项目的主要好处是建立了关于地外结构的严格结构设计框架，并对地外强地面运动进行识别和分类，作为量化相关危险的第一步。除了上述与空间探索和多行星殖民有关的目标外，这个项目成果的潜在应用可以是：(A)校准和开发将风化石块作为结构材料的3D打印技术；(B)利用土著材料实现中低收入国家的可持续住宅发展；(C)海底结构(在浮力/低重力条件下处于全球压缩状态下的拱形结构)的最佳抗震设计，可证明对深海勘探和采矿有用。

This project will investigate the behaviour of monolithic, adobe structures in low-gravity conditions, concluding to an optimal structural design framework for supporting future space exploration. Such structures will act as shielding to protect critical assets (such as robots, fuel tanks and power stations) and future inflatable structures (e.g. living quarters) from extreme conditions (radiation, sandstorms, temperature fluctuations) in an extraterrestrial environment. Linear and nonlinear numerical structural modelling and parametric static and dynamic analyses will identify the optimal design approach for utilising indigenous materials to produce such structures to minimise the weight burden on future manned explorations. The analytical work will be validated by experimental centrifuge tests which can simulate low gravity conditions at prototype scale. This will be the first systematic approach towards sustainable extraterrestrial structural design using methods and concepts developed for Earth. Until now, there have been isolated studies on conceptualising extraterrestrial structures given the challenges that needed to be addressed in such extreme environments, but there is not a systematic approach on how to realise these structures. Given the recent and ongoing research on the mechanical properties of regolith simulants, the proposed In-situ Resource Utilisation (ISRU) framework and the advances in 3D printing for extraterrestrial construction, it is timely to combine these fields with structural design strategies developed for Earth in order to identify optimal structural forms for use in low-gravity conditions, subject to extraterrestrial dynamic environmental actions. The first step for achieving this is the static approach and to identify from a wide class of monolithic vaults which is the optimal for long-span structures in low-gravity environments. The next step would be to identify engineering demand parameters from extraterrestrial natural hazards related to Lunar and Martian strong ground motions (shallow and deep moonquakes, marsquakes if available from the InSight mission and meteorite-impact generated ground motions). Subsequently, numerical models simulating different structural dynamic configurations (including soil-structure interaction, rocking and seismic isolation) will be implemented to conduct extensive linear and nonlinear dynamic analyses using the identified engineering demand parameters. This will result in the assessment of the dynamic performance of each different model and thus to the best structural option. However, a critical part is to validate the numerical models used in this project by centrifuge tests under the same extraterrestrial excitations. Nevertheless, it is out of the scope of this project to investigate the properties of regolith-based structural material since regolith simulants will be used for the experimental part of the project. The main benefit of this project is the establishment of a rigorous structural design framework regarding extraterrestrial structures and the identification and categorisation of the extraterrestrial strong ground motions as a first step for the quantification of the associated hazard. Aside from the aforementioned objectives related to space exploration and multi-planet colonisation, the potential applications of the results from this project can be: (a) the calibration and development of 3D-printing techniques incorporating regolith as a structural material; (b) the sustainable residential development of low- and middle-income countries using indigenous materials and (c) the optimal seismic design of submarine structures (arches in a global compression state under buoyancy/low gravity) that can prove useful for deep-ocean exploration and mining.