Acoustic transmission enhancement through a periodically-structured stiff plate without any opening

TL;DR

This paper demonstrates that a thin, stiff, periodically-structured plate can significantly enhance acoustic transmission in the subwavelength regime without openings, due to resonant excitation of Lamb modes, with potential ultrasonic applications.

Contribution

It reveals a novel mechanism for acoustic transmission enhancement in structured plates without openings, based on resonant Lamb mode excitation, supported by experimental and theoretical analysis.

Findings

Enhanced acoustic transmission observed experimentally and theoretically.

Resonant excitation of non-leaky Lamb modes identified as the key mechanism.

No openings required for transmission enhancement.

Abstract

We report both experimentally and theoretically that the enhanced acoustic transmission can occur in the subwavelength region through a thin but stiff structured-plate without any opening. This exotic acoustic phenomenon is essentially distinct from the previous related studies originated from, either collectively or individually, the interaction of the incident wave with openings in previous structures. It is attributed to the structure-induced resonant excitation of the non-leaky Lamb modes that exist intrinsically in the uniform elastic plate. Our finding should have impact on ultrasonic applications.