Experimental demonstration of rainbow trapping of elastic waves in two-dimensional axisymmetric phononic crystal platesa)

Chadi Ellouzi; Ali Zabihi; Louis Gormley; Farhood Aghdasi; Katerina Stojanoska; Amir Miri; Ratneshwar Jha; Chen Shen

doi:10.1121/10.0025179

Experimental demonstration of rainbow trapping of elastic waves in two-dimensional axisymmetric phononic crystal platesa)

J Acoust Soc Am. 2024 Mar 1;155(3):1759-1766. doi: 10.1121/10.0025179.

Authors

Chadi Ellouzi¹, Ali Zabihi¹, Louis Gormley¹, Farhood Aghdasi¹, Katerina Stojanoska¹, Amir Miri², Ratneshwar Jha¹, Chen Shen¹

Affiliations

¹ Department of Mechanical Engineering, Rowan University, Glassboro, New Jersey 08028, USA.
² Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.

PMID: 38436424
DOI: 10.1121/10.0025179

Abstract

Structures with specific graded geometries or properties can cause spatial separation and local field enhancement of wave energy. This phenomenon is called rainbow trapping, which manifests itself as stopping the propagation of waves at different locations according to their frequencies. In acoustics, most research on rainbow trapping has focused on wave propagation in one dimension. This research examined the elastic wave trapping performance of a two-dimensional (2D) axisymmetric grooved phononic crystal plate structure. The performance of the proposed structure is validated using numerical simulations based on finite element analysis and experimental measurements using a laser Doppler vibrometer. It is found that rainbow trapping within the frequency range of 165-205 kHz is achieved, where elastic waves are trapped at different radial distances in the plate. The results demonstrate that the proposed design is capable of effectively capturing elastic waves across a broad frequency range of interest. This concept could be useful in applications such as filtering and energy harvesting by concentrating wave energy at different locations in the structure.