Acoustic characterization of flexural metamaterial elements using an impedance tube

Abstract

Acoustic metamaterials have been a topic of interest in recent years and have enabled exotic effective fluid properties to be achieved, including those with negative or near-zero dynamic values. These extreme properties arise through the particular design of the microstructure, which make use of simple microscale acoustic elements to create the desired macroscopic characteristics. While many of these acoustic elements utilize the quasistatic motion of the surrounding fluid, recently thin elastic plates have been receiving more attention in the use of transmission-line acoustic metamaterials. Due to the high acoustic impedance and flexural coupling of the elastic material, the acoustic characterization of these elastic structures using traditional techniques such as an air-filled impedance tube presents a significant challenge. In this work, flexural elastic elements are examined in an acoustic impedance tube. Using theoretical formulations for elastic plates in conjunction with acoustic impedance tube mea...