AI 中文总结
研究由离散空间填充硬多边形或多面体组成的六种晶体的弹性行为，发现部分系统仅通过熵与几何相互作用呈现部分负泊松比行为，通过方形颗粒的两种实验实现证实了该现象的可行性与稳健性。
AI 中文摘要
负泊松比材料是指在一个方向受到压缩时，在一个或多个垂直方向也会压缩的系统。由于其违反直觉的力学性能，几十年来一直吸引着研究人员。它们的独特行为使其在减震器和压电传感器电极等广泛应用中具有潜力。大多数已知的负泊松比材料是通过以铰接方式连接刚性、各向异性单元来实现的，这种系统在微观尺度上往往难以通过实验实现。本文中，我们探索了由离散的空间填充硬多边形或多面体组成的六种晶体的弹性行为。我们表明，其中一些系统仅通过熵和几何的相互作用就表现出部分负泊松比行为。为了证明这种现象的可行性和稳健性，我们创建了方形颗粒的两种实验实现，包括由布朗运动驱动的胶体颗粒和由外部振动驱动的颗粒颗粒，并在两种情况下都证实了负泊松比的出现。
英文摘要
Auxetic materials - systems that, when subjected to a compression in one direction, also compress in one or more perpendicular directions - have intrigued researchers for decades due to their counterintuitive mechanical properties. Their unique behaviour gives auxetic materials potential for a wide range of applications such as shock absorbers, and electrodes in piezoelectric sensors. Most known auxetic materials are realized by connecting rigid, anisotropic units in a hinging manner, which are systems that often are hard to realize experimentally on the microscopic scale. Here, we explore the elastic behaviour of six crystals composed of discrete space-filling hard polygons or polyhedra. We show that some of these systems show partial auxetic behaviour, emerging from the interplay of entropy and geometry alone. To demonstrate the feasibility and robustness of this phenomenon, we create two experimental realizations of square-shaped particles, spanning both colloidal particles driven by Brownian motion and granular particles driven by external vibrations, and confirm the emergence of auxeticity in both cases.
