Novel composites with asymmetrical elastic wave properties
Novel composites with asymmetrical elastic wave properties
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DOI：
10.1016/j.compscitech.2015.03.007
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发表时间：
2015-06
影响因子：
9.1
通讯作者：
Langquan Shui;Z. Yue;Yong-shou Liu;Qingchang Liu;Jiaojiao Guo;Xin-Dang He
中科院分区：
文献类型：
--
作者：
Langquan Shui;Z. Yue;Yong-shou Liu;Qingchang Liu;Jiaojiao Guo;Xin-Dang He
传统的结构复合材料被认为是具有空间秩序的材料。本文将时间顺序引入到结构复合材料中。我们从理论上描述和数值上证明了一种结构复合材料具有可调的几乎“全带状”不对称弹性波特性。由于这种复合材料具有时空有序和非常规波动特性，因此可以将其命名为时空超材料（spatial - temporal metamaterial， STMM）。首先，基于改进的多尺度均质技术获得了有效材料参数，其中包括一些新的材料参数；其次，对非常规波的性质进行了理论分析。发现弹性波群速度面在STMM中不满足中心对称性，即违反了线弹性波的时间反转对称性。在某些情况下，波甚至是单向传播的。最后，我们给出了一个stmm的例子，包括均匀化计算和在某些方向上剪切波被禁止的数值模拟。本文提出的stmm的非常规波特性在吸声、声信息处理、节能和能量收集等方面具有诱人的潜在应用前景。
The traditional structural composites are known as materials with a spatial order. The temporal order is introduced into structural composites in this paper. We theoretically describe and numerically demonstrate the architecture for a structural composite which exhibits tunable and nearly “full-banded” asymmetrical elastic wave property. Given its spatiotemporal order and unconventional wave properties, such composite can be named as spatiotemporal metamaterial (STMM). Firstly, the effective material parameters, which include some new material parameters, are obtained based on improved multi-scale homogenization techniques. Secondly, the unconventional wave properties are theoretically analyzed. It is found that the elastic wave group velocity surfaces do not satisfy the centrosymmetry in STMM, i.e. the time-reversal symmetry of linear elastic wave is violated. In certain instances, the waves even propagate unidirectionally. Finally, we present an example of the STMMs, which includes homogenized calculations and numerical simulations where the shear waves are forbidden in some directions. The unconventional wave properties of the STMMs proposed in this paper own attractive potential applications, such as acoustic absorbing, acoustic information processing, energy-saving, and energy-harvesting.