Harnessing rainbow trapping via hybrid electromechanical metastructures for enhanced energy harvesting and vibration attenuation

Rainbow trapping is a phenomenon that enables vibration confinement due to the gradual variation of the wave velocity in space, which is typically achieved by means of locally resonant unit cells. In the context of electromechanical metastructures for energy harvesting, this strategy is employed to improve mechanical-to-electrical energy conversion and thereby to maximize the harvested power. In contrast to structures endowed with either mechanical or electromechanical resonators, we investigate a hybrid configuration that leverages the synergistic interplay between them. We compare numerical results for different grading laws in comparison to prior efforts on the topic, demonstrating enhanced energy harvesting and wideband vibration attenuation capabilities of the hybrid metastructure. We also discuss the formation of grading-induced localized modes and we shed light on the role of the motion of individual resonators on the overall power output increase. Published under an exclusive license by AIP Publishing.