Selective mode conversion and rainbow trapping via graded elastic waveguides

TL;DR

This paper demonstrates experimental control of elastic wave modes and energy trapping in a graded waveguide with resonators, enabling wave conversion and rainbow trapping for advanced wave manipulation.

Contribution

It introduces a novel elastic waveguide design with graded resonators that achieves simultaneous mode conversion and rainbow trapping through symmetry breaking.

Findings

Successful experimental demonstration of mode conversion.

Effective wave trapping via rainbow trapping mechanism.

Potential applications in wave manipulation and structural design.

Abstract

We experimentally achieve wave mode conversion and rainbow trapping in an elastic waveguide loaded with an array of resonators. Rainbow trapping is a phenomenon that induces wave confinement as a result of a spatial variation of the wave velocity, here promoted by gently varying the length of consecutive resonators. By breaking the geometrical symmetry of the waveguide, we combine the wave speed reduction with a reflection mechanism that mode-converts flexural waves impinging on the array into torsional waves travelling along opposite directions. The framework presented herein may open opportunities in the context of wave manipulation through the realization of structural components with concurrent wave conversion and energy trapping capabilities.