Regolith vibro-fluidization in space environments

颗粒自组装机制和基于颗粒或液滴的技术（如3d打印）正受到越来越多的关注，因为它们可能用于生产几乎任何形状的小型和大型新材料和/或结构。在空间探索领域，为各种应用组装和运输粒子是必不可少的，例如运输月球和火星土壤（通常是风化层）、采矿、研究地质方面和在月球或火星上建立栖息地。在这种情况下，直接在太空中合成复杂材料或在其他行星表面建造特定结构的能力是需要解决的主要挑战之一。然而，月球和火星的土壤很难处理，因为它们是由研磨性和活性物质构成的。在本项目中，将探索基于“振动”处理粒子的新策略。在微重力下，振动可以作为一种替代手段来控制分散在液体中的固体颗粒的动力学，迫使它们自组织并形成特定的三维复杂结构（可以用作特殊合金或其他材料的骨架）。在月球表面存在引力场的情况下，有可能利用振动迫使风化层（其特征是强烈的内部颗粒间摩擦）表现为“流体”，从而使其在几种应用中的运输和利用变得更加容易（例如，基础设施的3D打印，和/或风化层用作植物生长或提取O2和H2的固体支撑基质）。这些方面将通过结合理论、实验和数值工作来探索，并研究不同振幅和频率的振动诱导风化层型颗粒（模拟物）的自组织和/或“液化”的能力。除了“干”情况外，还将使用具有密度比的颗粒和流体进行地球重力条件下的实验，以便适当地模拟与月球上建立的条件相似的条件。

Particle self-assembly mechanisms and particle or droplet-based technologies (such as 3D-printing) are receiving an increasing interest due to their potential use for the production of new materials and/or structures at both small and large scales with virtually any shape. In the field of space exploration, it is essential to assemble and transport particles for various applications, for example transporting lunar and Martian soil (typically regolith), for mining, to study geological aspects and establish habitats on the Moon or Mars. The ability to synthesize complex materials directly in space or build specific structures on the surface of other planets is one the main challenges to be addressed in such a context. However, the lunar and Martian soils are difficult to handle, because they are made of abrasive and reactive materials. In the present project, novel strategies to handle particles based on "vibrations" will be explored. In microgravity, vibrations can be used as an alternate means to control the dynamics of solid particles dispersed in a liquid forcing them to self-organize and form specific three-dimensional complex structures (which can be used as backbones for special alloys or other materials). In the presence of a gravitational field such as that on the surface of Moon, there is potential to use vibrations to force regolith (which is characterized by strong internal inter-particle friction) to behave as a 'fluid' thereby making its transportation and utilization in the context of several applications much easier (e.g., 3D printing of infrastructures, and/or regolith utilization as a solid-support substrates for plant growth or for the extraction of O2 and H2). These aspects will be explored by combining theoretical, experimental and numerical work, and studying the ability of vibrations with different amplitudes and frequency to induce self-organization and/or "liquefaction" of regolith-type particles (simulants). In addition to "dry" cases, experiments in terrestrial gravity conditions will be conducted using particles and fluids with density ratio such that conditions similar to those established on the moon are properly mimicked.