Bending a periodically layered structure for transformation acoustics

TL;DR

This paper introduces a new method using periodically layered structures with bent plates to achieve transformation acoustics, enabling acoustic cloaking and illusions with simple metamaterials.

Contribution

It develops a novel approach combining layered structures and transformation acoustics for designing acoustic devices with specific functionalities.

Findings

High refractive index achieved normal to bent plates

Effective acoustic cloaking demonstrated

Layered structure enables sound manipulation in designed shapes

Abstract

Anisotropic acoustic metamaterials have been proved very useful for their high potential in guiding and manipulating sound energy. In this paper, we further develop the idea by using periodically layered structures for transformational acoustics. Such a simple scheme periodically inserts identically bent solid plates in a background fluid. It forms a metamaterial with high refractive index normal to the curved plates and an index near to one along the plates. We show that the periodically layered structure, combined with transformation approach, can be cut into particular device shapes for acoustic cloaking and illusion.