ENERGY HARVESTING ANALYSIS OF A PIEZOELECTRIC CANTILEVER BEAM WITH MAGNETS FOR FLOW-INDUCED VIBRATION

Flow-induced vibration contains tremendous energy. Based on the theory of flow-induced vibration, a kind of flow-induced vibration energy harvester with additional magnetic excitation is designed, and its vibration energy harvesting characteristics are studied theoretically and experimentally. The harvester consists of a piezoelectric cantilever beam, a circular cylinder and magnets. Firstly, based on the Euler-Bernoulli beam theory, the energy functions of the magneto-piezoelectric energy harvester with fluid-induced vibration excitation are derived, and the electromechanical coupling equation is established by using the Hamilton principle. Then, the influence of the system parameters such as the flow velocity, the diameter and length of the circular cylinder, the magnetic parameters and the external resistance on the vibration characteristics and output voltage of the piezoelectric energy harvester. The results show that the vibration amplitude of the piezoelectric harvester produces vortex-induced vibration at low flow velocity and output the maximum voltage; the magnetic force can reduce the resonance frequency of the structure and broaden the bandwidth harvester. Thus, the magnetized piezoelectric harvester is more suitable for low-speed flow environment than the non-magnetized piezoelectric harvester. The experimental results agree well with the numerical results, which verifies the results of the theoretical analysis of the magneto-piezoelectric energy harvester.