Harnessing instabilities for design of soft reconfigurable auxetic/chiral materials
Harnessing instabilities for design of soft reconfigurable auxetic/chiral materials
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DOI：
10.1039/c3sm51148k
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发表时间：
2013-01-01
期刊：
影响因子：
3.4
通讯作者：
Bertoldi, Katia
中科院分区：
文献类型：
--
作者：
Shim, Jongmin;Shan, Sicong;Bertoldi, Katia
大多数材料都具有针对特定属性和功能进行优化的独特形式。然而，根据刺激重新配置材料结构的能力打开了令人兴奋的机会。虽然机械不稳定性传统上被视为一种故障模式，但在这里，我们利用它们来设计一类2D软材料，其结构可以根据外部刺激而发生显着变化。通过考虑几何约束的2D欧几里得平面的镶嵌，我们已经确定了四种可能的周期性分布的均匀圆孔，其中机械不稳定性可以利用可逆的扩展（即与圆孔）和紧凑（即与细长的，几乎封闭的椭圆形孔）之间的切换周期性配置。有趣的是，在所有这些结构的屈曲被发现诱导大的增量泊松比的负值，并在其中两个也形成手征图案。使用有限元模拟和实验相结合，在厘米级，我们证明了所提出的材料的概念验证。由于所提出的可重构材料的机制是由弹性不稳定性引起的，因此它是可逆的、可重复的和与尺度无关的。
Most materials have a unique form optimized for a specific property and function. However, the ability to reconfigure material structures depending on stimuli opens exciting opportunities. Although mechanical instabilities have been traditionally viewed as a failure mode, here we exploit them to design a class of 2D soft materials whose architecture can be dramatically changed in response to an external stimulus. By considering geometric constraints on the tessellations of the 2D Euclidean plane, we have identified four possible periodic distributions of uniform circular holes where mechanical instability can be exploited to reversibly switch between expanded (i.e. with circular holes) and compact (i.e. with elongated, almost closed elliptical holes) periodic configurations. Interestingly, in all these structures buckling is found to induce large negative values of incremental Poisson's ratio and in two of them also the formation of chiral patterns. Using a combination of finite element simulations and experiments at the centimeter scale we demonstrate a proof-of-concept of the proposed materials. Since the proposed mechanism for reconfigurable materials is induced by elastic instability, it is reversible, repeatable and scale-independent.