An Experimental Analysis of an Active Elastic Metamaterial
An Experimental Analysis of an Active Elastic Metamaterial
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DOI：
10.3182/20140313-3-in-3024.00169
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
S. Pope;H. Laalej;V. Kadirkamanathan
中科院分区：
文献类型：
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作者：
S. Pope;H. Laalej;V. Kadirkamanathan
弹性和声学超材料提供了一种方法来创造具有天然或传统材料所没有的特性的材料。这尤其包括动态有效材料特性，即密度和模量，其在规定的频带中可以变为负值。弹性和声学超材料为声学中存在的问题提供了替代解决方案，并为实现新的新概念提供了途径。与超材料相关的新概念包括声学不可见性和亚波长成像。具有负有效参数的弹性异向介质可以用局部谐振器阵列来实现。然而，由于有效参数为负的固定且通常较窄的频带，这些设备的性能受到影响。有源超材料提供了一种替代方法，其中施加到传输介质上的控制力模拟所需的响应。这样的装置具有能够实现响应的益处，该响应是可调谐的并且单独使用无源部件是不可能的。本文重点发展的实验演示的主动弹性超材料与负的质量或刚度跨越所需的频带。主动弹性超材料是由一系列受约束的集中质量组成的一维结构，通过反馈控制向集中质量施加控制力。利用最小二乘法从测量数据中提取动态有效参数，以将数据拟合到有效系统。将实验测量的有效参数与仿真结果进行比较，验证了主动弹性超材料在实验中的有效响应。
Abstract Elastic and acoustic metamaterials provide an approach to creating materials which possess properties which are not found in natural or conventional materials. This notably includes dynamic effective material properties, i.e. density and modulus, which can become negative in prescribed frequency bands. Elastic and acoustic metamaterials provide alternative solutions to existing problems in acoustics and provide a route to realizing novel new concepts. Novel concepts associated with metamaterials include acoustic invisibility and sub-wavelength imaging. Elastic metamaterials with negative effective parameters can be realized using arrays of local resonators. However the performance of these devices suffers due to a fixed and usually narrow frequency band in which the effective parameters are negative. Active metamaterials provide an alternative approach in which control forces applied to a transmission medium emulate the desired response. Such devices have the benefit of being able to realize a response which is both tunable and not possible with passive components alone. This paper focuses on the development of an experimental demonstration of active elastic metamaterials with negative mass or stiffness across desired frequency bands. The active elastic metamaterial is a one-dimensional structure composed of a series of constrained lumped masses to which control forces are applied through a feedback control. The dynamic effective parameters are extracted from the measured data using a least squares approach to fit the data to an effective system. Comparison of the measured effective parameters to the simulated results verifies the effective response of the active elastic metamaterial in experimentation.