Laboratory of Science and Technology on Integrated Logistics Support, National University of Defense Technology, Changsha, Hunan, 410073, China.
Institut des NanoSciences de Paris (INSP-UMR CNRS 7588), Université Pierre et Marie Curie, (Box 840) 4, Place Jussieu, 75252, Paris Cedex 05, France.
Nat Commun. 2017 Nov 3;8(1):1288. doi: 10.1038/s41467-017-00671-9.
Linear acoustic metamaterials (LAMs) are widely used to manipulate sound; however, it is challenging to obtain bandgaps with a generalized width (ratio of the bandgap width to its start frequency) >1 through linear mechanisms. Here we adopt both theoretical and experimental approaches to describe the nonlinear chaotic mechanism in both one-dimensional (1D) and two-dimensional (2D) nonlinear acoustic metamaterials (NAMs). This mechanism enables NAMs to reduce wave transmissions by as much as 20-40 dB in an ultra-low and ultra-broad band that consists of bandgaps and chaotic bands. With subwavelength cells, the generalized width reaches 21 in a 1D NAM and it goes up to 39 in a 2D NAM, which overcomes the bandwidth limit for wave suppression in current LAMs. This work enables further progress in elucidating the dynamics of NAMs and opens new avenues in double-ultra acoustic manipulation.
线性声子晶体（LAMs）被广泛用于操控声波，然而，通过线性机制获得具有广义带宽（带隙宽度与起始频率之比）>1 的带隙是具有挑战性的。在这里，我们采用理论和实验的方法来描述一维（1D）和二维（2D）非线性声子晶体（NAMs）中的非线性混沌机制。该机制使得 NAMs 能够在超低频和超宽带范围内（由带隙和混沌带组成）将波的传输降低 20-40dB。通过亚波长单元，1D NAM 的广义带宽达到 21，2D NAM 的广义带宽达到 39，这克服了当前 LAMs 中对波抑制的带宽限制。这项工作促进了对 NAMs 动力学的进一步研究，并为双超声操控开辟了新途径。
