Design And Modeling A Frequency Self-Tuning Vibration Energy Harvester For Rotational Applications

Vibration energy harvester (VEH) for rotational applications has attracted increasing attentions in the last decade, and one of the major challenges is still the mismatch between the resonant frequency of the VEH and the rotational frequency. To solve this issue, the frequency matching mechanism of the VEH applied to rotating environment is studied and a self-tuning piezoelectric VEH is proposed. The main advantage of the proposed VEH is that the effective beam length is changed by centrifugal force while the stiffness of the beam is changed by rigid-flexible coupling effect, which is the key to realize frequency matching in a wide frequency range. Then an accurate rigid-flexible coupling model for the proposed VEH is established with Hamiltonian variational principle, and a finite element model is built for numerical analysis. Finally, the established model is used to study the proposed VEH. Numerical analysis results show that the proposed VEH can achieve frequency matching within the frequency range of 8-28 Hz, and the power output is 0.42-0.74 mW. Numerical analysis results also show that the frequency tuning mass introduced as an independent parameter in VEH is of great significance to improve the frequency matching range, and also makes the structure design flexible. (c) 2021 Elsevier Ltd. All rights reserved.