Acoustic Meta-Structures based on Periodic Acoustic Black Holes: Dispersion and Propagation Characteristics

摘要

Acoustic Black Holes (ABHs) are power-law geometric inhomogeneities, typically embedded in thin-walled structural elements, that provide an effective approach to control the spatial distribution of the phase and group velocity. Periodic arrangements of ABHs can be used to assign metamaterial-like properties to the host structure and to carefully tailor the dispersion and propagation characteristics; the resulting structures are referred to as meta-structures. In this paper, we present a numerical study to explore the peculiar dynamic characteristics of these meta-structures compared to traditional designs. Results show that the use of periodic tapers allows achieving remarkable dispersion properties such as zero group velocity points in the fundamental Lamb modes and strong mode conversion mechanisms. The dispersion properties and transmission behavior are numerically investigated using finite element analysis. Possible applications of the dispersion characteristics, like beam collimation or splitter, are also explored.