Selective Mode Conversion and Rainbow Trapping via Graded Elastic Waveguides

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 res-onators. 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 traveling in 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.

Automated summary

Experimental success in achieving wave-mode conversion and rainbow trapping in an elastic waveguide loaded with an array of resonators. Rainbow trapping induced by spatial wave velocity variation through gently changing consecutive resonator lengths, combined with wave-speed reduction and reflection mechanism for flexural wave mode conversion into torsional waves. Framework may offer opportunities in wave manipulation through structural components with concurrent wave-conversion and energy-trapping capabilities.