一种稳健的“收缩包裹”分段构造将三维网格结构转化为力学超材料
A Robust "Shrink-and-wrap" Piecewise Construction Transforms 3-Dimensional Mesh Structures into Mechanical Metamaterials
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中文总结 AI 辅助
本研究提出一种“收缩包裹”分段构造方法，可将任意三角形或四面体网格结构转化为具有负泊松比和局部可编程力学性质的拉胀力学超材料，并适用于3D打印。
中文摘要 AI 辅助
力学超材料是一类凭借其微结构架构而展现出自然界中不常见的力学性质的材料：例如，拉胀力学超材料是在变形力作用下具有负泊松比的材料。然而，除了由大致相同的单元胞组成的相对简单的晶体、晶格或重复图案架构之外，像拉胀材料这样的力学超材料在设计上非常困难，尤其是在所有三个维度上。在这里，我们表明，对于任何可以分解为三角形或四面体网格的结构，这些结构可以经受一种简单的变换，该变换在这些三角形或四面体单纯形内创造条件，无论其个体几何形状如何，都会引入一个反向旋转的多边形/多面体机制，该机制既保证了负泊松比，又允许局部可编程的力学性质。我们将这种“收缩包裹”构造应用于从日益复杂的3D结构生成力学超材料，首先从简单的（凸）多面体开始；然后，扩展到具有任意大数量顶点并使用构造实体几何（CSG）和3D扫描设计的结构；最终，扩展到从手机摄像头拍摄的视频生成的3D物体——使得可能任何设计或现实世界中发现的物体或几何结构都能转化为力学超材料。我们表明，这些整体式拉胀结构仍然可以通过增材制造技术轻松进行3D打印。我们期望这种分段方法能够设计任意复杂的力学超材料结构，从而在需要可编程内部重构和/或力重定向的众多潜在应用中发挥作用，这些应用跨越并贯穿其3D几何体。
英文摘要
Mechanical metamaterials are materials that, by virtue of their microstructural architectures, exhibit mechanical properties not often found in nature: for example, auxetic mechanical metamaterials are materials that possess a negative Poisson's ratio in response to deforming forces. However, outside of relatively simple crystalline, lattice-based, or repeating-pattern architectures composed of mostly identical unit cells, mechanical metamaterials like auxetics are notoriously difficult to design, particularly across all three dimensions. Here we show that, for any structure that can be decomposed into triangular or tetrahedral meshes, those structures can be subjected to a simple transformation that that creates conditions within those triangular or tetrahedral simplexes that, regardless of their individual geometries, introduces a counter-rotating polygon/polyhedron mechanism that both guarantees a negative Poisson ratio and allows locally programmable mechanical properties. We apply this "shrink-and-wrap" construction to generate mechanical metamaterials from increasingly complex 3D structures, first from simple (convex) polyhedrons; then, to designs with arbitrarily large numbers of vertices and designed using constructive solid geometry (CSG) and 3D scanning; and, ultimately to 3D objects generated from videos captured by mobile phone camera -- making potentially any object or geometric structure designed or found in the real world transformable into a mechanical metamaterial. We show that these monolithic auxetic constructions remain readily 3D-printable via additive manufacturing techniques. We expect this piecewise approach to designing arbitrarily complex mechanical metamaterial structures can enable numerous potential applications where programmable internal reconfigurations and/or force redirection are required across and throughout their 3D geometries.
发表机构
- Stony Brook University, the State University of New York (SUNY)（纽约州立大学石溪分校）
- Department of Biomedical Engineering（纽约州立大学石溪分校工程与应用科学学院）
- College of Engineering and Applied Sciences (CEAS)
- Stony Brook University, SUNY
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