Enhancement of vibration energy harvesting using a combination of acoustic black holes and meta structures
Alireza Sangsefidi, Davood Younesian
Abstract
This study presents and investigates a novel piezoelectric energy harvester. The proposed harvester comprises a cantilever beam with an embedded acoustic black hole (ABH) structure, a piezoelectric patch, and an auxetic booster between the ABH structure and the piezoelectric patch. The ABH structure reduces the energy harvesting frequency and creates a region with high energy density. Auxetic boosters enhance energy transfer from the substrate to the piezoelectric patch. The proposed harvester has been investigated numerically and experimentally. The conversion of the uniform beam to the ABH beam reduced the first natural frequency from 128 Hz to 26 Hz and increased the harvester’s output power from 207 µW to 408 µW. The investigation found that all the examined boosters increased the output power of the ABH harvester. The simple, reentrant, anti-chiral, and chiral boosters enhanced the output power by 2, 6, 5, and 5, respectively. The superior increase in output power by auxetic boosters compared to a simple booster can be attributed to the auxetic property (negative Poisson’s ratio and specific deformation mechanism) inherent to these structures. Incorporating boosters did not result in a notable alteration to the harvester’s natural frequencies.