Enhancement of the low-frequency acoustic energy harvesting with auxetic resonators

Abstract

A new concept to enhance efficiency of the acoustic energy harvesting is presented and experimentally tested in this paper. An auxetic latticed resonator backed by an acoustic rectangular tube is proposed for this purpose. The concept is tested and proved by comparing the extracted power against performance of a conventional cantilever resonator at resonant-resonant condition. The problem is modeled by the Finite Element Method. The models are validated using experimental tests. The energy harvesting performance is numerically evaluated in different sound powers, geometrical aspects and electrical properties. In a parametric study, performance of the proposed auxetic resonator is compared with a plain one. It is shown that employing the concept can remarkably enhance performance of the acoustic energy harvesting system. At low frequencies, 138 Hz in this study, at an optimum situation we could arrive at a large magnification factor around 10.5 for 100 dB sound pressure level.