Plewa Julian, Płońska Małgorzata, Lis Paweł
Faculty of Science and Technology, Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty Str. 1a, 41-500 Chorzów, Poland.
Materials (Basel). 2022 Apr 13;15(8):2848. doi: 10.3390/ma15082848.
Auxetic structures exhibit unusual changes in size, expanding laterally upon stretching instead of contracting. This paper presents this effect in a failsafe mode in structures made of rigid squares. We applied the concept of auxetic structures made of rigid rotating squares (from Grima and Evans) and offer a novel solution for connecting them. By introducing axes of rotation on the surface of the squares, a reliable working system is obtained, free from stress, in which the squares can come into contact with each other and completely cover the surface of the structure, or, in the open position, form regularly arranged pores. Herein, we present a new 2D auxetic metamaterial that is mathematically generated based on a theoretical relationship of the angle between the edges of a square and the position of the axis of rotation. Physical models were generated in the form of a planar structure and in the form of a circular closed structure. Such physical models confirmed our initial considerations and the geometrical relationships, offering new application possibilities. The novel structure that was designed and manufactured for the purpose of the paper can be considered as a new proposal in the market of auxetic materials.
负泊松比结构呈现出不同寻常的尺寸变化，在拉伸时横向扩展而非收缩。本文在由刚性正方形构成的结构中以一种故障安全模式展示了这种效应。我们应用了由刚性旋转正方形构成的负泊松比结构的概念（源自格里马和埃文斯），并提供了一种连接它们的新颖解决方案。通过在正方形表面引入旋转轴，可获得一个无应力的可靠工作系统，在该系统中正方形能够相互接触并完全覆盖结构表面，或者在打开位置形成规则排列的孔隙。在此，我们展示了一种新的二维负泊松比超材料，它是基于正方形边之间的角度与旋转轴位置的理论关系通过数学方法生成的。物理模型以平面结构和圆形封闭结构的形式生成。这些物理模型证实了我们最初的设想和几何关系，提供了新的应用可能性。为本文目的而设计和制造的新颖结构可被视为负泊松比材料市场中的一项新提议。
