Modeling and experiment of vibro-impact vibration energy harvester based on a partial interlayer-separated piezoelectric beam

Piezoelectric-based energy harvesting techniques offer a promising way to transform vibration energy into electric energy. However, many vibration energy harvesters (VEH) can only work under narrow bandwidths and limited high frequencies to restrict their working performance. In this paper, a vibro-impact piezoelectric VEH is proposed, where a partial interlayer-separated piezoelectric beam is designed to improve the voltage output and frequency bandwidth of the VEH. First, the mechanism of the proposed VEH is introduced and the electromechanical model is derived based on the Euler-Bernoulli beam theory and vibro-impact dynamic model. Voltage-frequency responses are then obtained by using an approximate analytical method. In addition, the effect of partial interlayer-separated piezoelectric beams on the energy harvesting performance is investigated numerically. A parametric study is performed to investigate the influence of system parameters on the voltage output in terms of bandwidth and magnitude. Finally, the theoretical solutions are validated by experimental results, the voltage output of the proposed VEH is higher than the non-impact type. The maximum output power of the proposed VEH is about 12 times more than that of the conventional one under a 0.2 g acceleration. Due to the good agreement of the variation trend between the theoretical values and experiment results, the proposed partial interlayer-separated beam VEH can be used for a further optimization of the vibration energy harvester.