Characterization of a newly developed class of passive nonreciprocal acoustic metamaterials is presented in an attempt to quantify their ability of controlling the flow and distribution of acoustic energy in acoustic cavities and systems. The proposed nonreciprocal acoustic metamaterial (NAMM) cell consists of a one-dimensional acoustic cavity provided with piezoelectric flexible boundaries connected to an array of anti-parallel diodes to introduce the nonlinear damping effect that tends to break the reciprocity of the energy flow through the NAMM cell. A comprehensive experimental characterization of prototypes of the NAMM cells is presented here in order to investigate the effect of various anti-parallel diode arrangements on the nonreciprocal behavior of the cell. Furthermore, the experimental characterization aims also at demonstrating the effectiveness of the proposed NAMM in tuning the directivity, flow, and distribution of acoustic energy propagating through the metamaterial.

中文翻译：

---

具有反并联二极管的一维不可逆声学超材料的实验表征

提出了一种新开发的一类无源不可逆声学超材料的特性，以试图量化它们控制声腔和系统中声能的流动和分布的能力。拟议的不可逆声学超材料（NAMM）单元由一维声学腔组成，该腔具有压电柔性边界，该压电柔性边界连接到反并联二极管阵列，以引入非线性阻尼效应，该效应倾向于破坏通过NAMM的能量流的互易性细胞。NAMM原型的全面实验表征为了研究各种反并联二极管排列对电池的不可逆行为的影响，在此介绍电池。此外，实验表征还旨在证明所提出的NAMM在调节通过超材料传播的声能的方向性，流量和分布方面的有效性。