Investigation on acoustic energy harvesting based on quarter-wavelength resonator phononic crystals

Abstract

This article presents the development of an acoustic energy harvester using a quarter-wavelength resonator phononic crystals together with piezoelectric vibrators. The quarter-wavelength resonator phononic crystals consist of a main wave duct, several quarter-wavelength resonators, and equivalent piezoelectric vibrators. The acoustic energy is converted to mechanical energy when the sound incident in the quarter-wavelength resonator generates an oscillatory pressure as of localization efficiency, which in turns causes piezoelectric vibrators vibrating. Transfer matrix method is used to provide a physical insight into the structure band of the quarter-wavelength resonator phononic crystals, and finite element method is used to analyze the sound localization effect and evaluate the reclaimed energy of the quarter-wavelength resonator phononic crystals. Results indicate that the numerical analysis agrees well with experiments. When the frequencies of the incident sound are near both sides of the bandgap, the maximum output voltage always can be obtained.