Title: Combinatorial Design of Textured Mechanical Metamaterials Show Chinese title

Title: 纹理机械超材料的组合设计

Abstract: The structural complexity of metamaterials is limitless, although in practice, most designs comprise periodic architectures which lead to materials with spatially homogeneous features. More advanced tasks, arising in e.g. soft robotics, prosthetics and wearable tech, involve spatially textured mechanical functionality which require aperiodic architectures. However, a na\"ive implementation of such structural complexity invariably leads to frustration, which prevents coherent operation and impedes functionality. Here we introduce a combinatorial strategy for the design of aperiodic yet frustration-free mechanical metamaterials, whom we show to exhibit spatially textured functionalities. We implement this strategy using cubic building blocks - voxels - which deform anisotropically, a local stacking rule which allows cooperative shape changes by guaranteeing that deformed building blocks fit as in a 3D jigsaw puzzle, and 3D printing. We show that, first, these aperiodic metamaterials exhibit long-range holographic order, where the 2D pixelated surface texture dictates the 3D interior voxel arrangement. Second, they act as programmable shape shifters, morphing into spatially complex but predictable and designable shapes when uniaxially compressed. Third, their mechanical response to compression by a textured surface reveals their ability to perform sensing and pattern analysis. Combinatorial design thus opens a new avenue towards mechanical metamaterials with unusual order and machine-like functionalities. Show Chinese abstract

Abstract: 超材料的结构复杂性是无限的，尽管在实践中，大多数设计包含周期性结构，这导致具有空间均匀特性的材料。 更高级的任务，例如在软体机器人、假肢和可穿戴技术中出现的任务，涉及需要非周期性结构的空间纹理机械功能。 然而，这种结构复杂性的简单实现往往会引发挫折，这会阻止协同操作并阻碍功能。 在这里，我们介绍一种组合策略，用于设计非周期但无挫折的机械超材料，我们展示了它们表现出空间纹理功能。 我们使用立方体构建块——体素——来实现这一策略，这些体素各向异性变形，以及一种局部堆叠规则，该规则通过保证变形的构建块像三维拼图一样适配，从而允许协作形状变化，并使用3D打印。 我们证明，首先，这些非周期性超材料表现出长距离全息秩序，其中二维像素化表面纹理决定了三维内部体素排列。 其次，它们作为可编程形状转换器起作用，在单轴压缩时可以转变为空间复杂但可预测和可设计的形状。 第三，它们对由纹理表面压缩的机械响应揭示了它们执行传感和模式分析的能力。 因此，组合设计为具有不寻常秩序和类似机器的功能的机械超材料开辟了一条新途径。