A multi-layer active elastic metamaterial with tuneable and simultaneously negative mass and stiffness
A multi-layer active elastic metamaterial with tuneable and simultaneously negative mass and stiffness
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DOI：
10.1088/0964-1726/23/7/075020
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发表时间：
2014-06
影响因子：
4.1
通讯作者：
S. Pope;H. Laalej
中科院分区：
文献类型：
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作者：
S. Pope;H. Laalej
所有传统的声学/弹性介质都被限制为具有正常数的本构参数（密度和模量）。超材料提供了一种可以打破这种限制的方法。通过使这些参数为负和/或可调谐，更宽范围的特性变得可能。本文介绍了声学/弹性超材料，其中的材料参数可以同时在一个有限的频带和独立的可调的需求的参数的大小为负的第一个实验实施。该设计是一种主动超材料（元机械系统），其通过直接向超材料内的每一层施加反馈控制力来实现。调整负参数的大小的能力对于使用可以针对特定应用进行调整的标准设计或者可以适应变化的性能要求的标准设计具有重要意义。该设计实现了相对较大的尺度和较低的频率，但单位胞长明显小于双负波段的波长。重要的是，假设适当的控制硬件是可用的，该设计可以在比例上减小并扩展到更大的自由度。
All conventional acoustic/elastic media are restricted to possess positive constants for their constitutive parameters (density and modulus). Metamaterials provide an approach through which this restriction can be broken. By making these parameters negative and/or tuneable a broader range of properties becomes possible. This paper describes the first experimental implementation of an acoustic/elastic metamaterial in which the material parameters can be both simultaneously negative in a finite frequency band and the magnitude of the parameters independently tuneable on demand. The design is an active metamaterial (meta-mechanical-system) which is realized by directly applying feedback control forces to each layer within the metamaterial. The ability to tune the magnitude of the negative parameters has important implications for the use of a standard design that can be tuned to a particular application, or one which can adapt to a changing performance requirement. The implementation of the design is relatively large scale and low frequency, but the unit-cell length is significantly smaller than the wavelength in the double negative band. Importantly, assuming appropriate control hardware is available, the design can be both reduced in scaled and expanded to greater degrees of freedom.