Acoustic energy harvesting meta-surface by coupling nonlinear Helmholtz resonator and auxetic structure

Abstract

Conventional acoustic energy harvesting device or material suffer from low efficiency. This study proposes a novel acoustic energy harvesting meta-surface (AEHMS) capable of achieving acoustic energy collection by coupling nonlinear Helmholtz resonator and auxetic structure. This meta-surface exhibits subwavelength characteristics and satisfies the conditions of the long-wave limit. The efficiency is increased by the following 3 aspects: 1. Nonlinear effects of Helmholtz resonator is introduced and optimized with Melnikov's method 2. The auxetic structure is introduced and optimized with higher acousticvibration energy conversion efficiency. 3. The coupling of two sub-system is optimized with higher coupling force at desired frequency band. Finally, the numerical simulation results of AEHMS were validated through experimental verification, demonstrating that AEHMS exhibits outstanding energy harvesting performance. At an input excitation sound pressure level of 100 dB, the metasurface with ultra-thin thickness (approximately 11 cm thick, equivalent to 1/12 of the wavelength at a center frequency of 250 Hz) achieves a maximum output voltage of 1.33 V -nearly 31 times than conventional piezoelectric beam and a maximum output electrical power of 56.64μW.