Energy scavenging from acousto-elastic metamaterial using local resonance phenomenon

摘要

This article presents the possibility of energy scavenging (ES) utilizing the physics of acousto-elastic metamaterial (AEMM) and use them in a dual mode (Acoustic Filter and Energy Harvester), simultaneously. Concurrent wave filtering and energy harvesting mechanism is previously presented using local resonance phenomenon in phononic crystal, however energy harvesting capabilities of AEMM is not reported extensively. Traditionally acoustic metamaterials are used in filtering acoustic waves by trapping or guiding the acoustic energy, whereas this work presents that the trapped dynamic energy inside the soft constituent (matrix) of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell model, we asserted that at lower acoustic frequencies maximum power in the micro Watts (～36μW) range can be generated, which is significantly higher than the existing harvesters of same kind. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. In this work we propose sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a broadband energy scavenger (ES) with multi-cell model is designed with varying geometrical properties.