Nonlinear analysis of flexoelectric acoustic energy harvesters with Helmholtz resonator

Abstract

Abstract A Helmholtz resonator-type flexoelectric acoustic energy harvester (HR-FAEH) is proposed in this paper. It is realized by replacing the cavity bottom plate of Helmholtz resonator with a disk vibrator, which is a circular plate attached flexoelectric films on both sides. The environmental sound wave is amplified by the resonator in its cavity, and stimulates the vibration of the disk oscillator to generate electric energy. Due to the large sound pressureamplified by theHelmholtz resonator, the disk vibrator will suffer large deformation. If using the small deformation theory to predict the voltage could result in significant errors of up to 60 percent. To address this issue, the system is optimized by considering large deformation. The nonlinear electromechanical governing equations of the disk vibrator are derived by Hamiltonian principle, discretized by Galerkin method and solved by Incremental Harmonic Balance method (IHB). The present results are verified by the finite element simulation. Results show that adjusting the relation between the resonant frequencies of the Helmholtz resonator and the disk vibrator can increase voltage output by 36.5 percent compared to the linear model.