Continuous Design and Reprogramming of Totimorphic Structures for Space Applications

Throughout nature, the intricate and disordered lattice structures that are observed in bones, plant stems, dragonfly wings, coral, radiolarians [1], amongst many other examples, demonstrate how powerful geometry is for designing structures with extreme mechanical properties from a very limited selection of base materials [2]. Metamaterials [3] are a recent example of human-engineered lattice structures that utilise the geometric design space of unit cells to change the properties of the lattice obtained by tiling this motive, often producing structures with different properties than those of the underlying lattice material - for instance, having a soft and compressible lattice made of a very brittle material such as ceramic [4]. In addition to metamaterials that follow a periodic design philosophy, there is a growing interest in (inversely) designing disordered lattice materials and structures [5-12], allowing us to fully tap into the functional design space explored by nature. Since lattices can be constructed using additive manufacturing, they combine ease of manufacturing with a highly expressive design space that only requires a small amount of building materials. It is not surprising that lattices have found applications on a variety of scales, ranging from nano-and mesoscale materials to large-scale structures such as space habitats [13-16]. The static nature of lattices also means that once they have been constructed, their properties are fixed - unless physically stimulating the lattice changes the properties of its base materials or allows switching between different shapes (e.g., magnetically [17-19]), therefore enabling a certain degree of reprogrammability of the lattice's properties; also known as active metamaterials [20, 21].