Negative extensibility metamaterials: Occurrence and design-space topology
Negative extensibility metamaterials: Occurrence and design-space topology
复制标题
DOI：
10.1103/physreve.96.023002
复制
发表时间：
2017-08-07
影响因子：
2.4
通讯作者：
Klein, John T.
中科院分区：
文献类型：
--
作者：
Karpov, Eduard G.;Danso, Larry A.;Klein, John T.
当外部拉伸载荷达到某一临界水平时，负延伸性材料结构拉回并收缩。在本文中，我们揭示了负责这种不寻常的力学性能的非线性应变能函数的基本数学特征。一个系统的讨论导致一个全面的相图方面的设计参数为一个简单的单胞结构，提供了一个全景的所有可能的非线性力学行为。图中清楚地标识了负可扩展性区域。所寻求的属性被认为是罕见的，只发生在一个非常窄的设计参数范围。尽管如此，由于所研究的结构的简单性，我们认为，负延展性应该是一个更常见的现象比以前认为的。它可以出现在由几个线性弹性连杆组成的简单的单胞中，尽管它们的性质有一些特殊的组合。这些非线性单元可以用来设计周期性的机械超材料，其例子以及创新的建筑超结构。
A negative extensibility material structure pulls back and contracts when the external tensile load reaches a certain critical level. In this paper, we reveal basic mathematical features of the nonlinear strain energy function responsible for this unusual mechanical property. A systematic discussion leads to a comprehensive phase diagram in terms of design parameters for a simple unit cell structure that provides a panoramic view of all possible nonlinear mechanical behaviors. A negative extensibility region clearly is identified in the diagram. The sought property is seen to be rare, occurring only for a very narrow range of the design parameters. Nonetheless, due to the simplicity of the studied structure we suggest that the negative extensibility should be a more common phenomenon than previously thought. It can appear in simple bistable cells made of only several linearly elastic links, although at some peculiar combinations of their properties. These bistable unit cells can be used to design periodic mechanical metamaterials whose examples are shown as well as innovative architectural metastructures.