Perspective: Acoustic Metamaterials in Future Engineering

Abstract

Acoustic metamaterials (AMMs) are a type of artificial materials that make use of appropriate structural designs and exhibit exotic properties not found in natural materials, such as negative effective material parameters (e.g., bulk modulus, mass density, and refractive index). These interesting properties offer novel means for sound manipulation and thus have drawn a great deal of attention. Over the past two decades, tremendous progress has been made in the fundamental research of AMMs, which has not only promoted the development of modern acoustics but also shown the potential of AMMs for engineering applications. Here, we review recent developments in AMMs with a focus on their future engineering, especially in the most promising fields of sound absorption/isolation, acoustic imaging, cloaking, and so on, furthermore, we outline the opportunities and challenges they are encountering.