Theoretical modelling and analysis of piezoelectric vibration energy harvester based on stepped variable thicknesses cantilever beam with magnetic force
Abstract：Vibration energy harvesting can be designed as self-powered devices for low power electronic such as wireless sensor network and wearable electronics. Thus, it have attracted much attention in recent years. In this work, a piezoelectric vibration energy harvester (PVEH) based on stepped variable thicknesses cantilever beam with magnetic force is proposed. First, the nonlinear magnetic force is introduced and the energy functions are obtained by using Euler-Bernoulli beam theory. The Lagrange Equation is applied to establish the coupled electromechanical dynamics equation. Finally, the influence of the distance between two magnets on the vibration characteristics of the system is examined. Moreover, the mono-stable and bi-stable responses are analyzed, and the effects of the distance between two magnets and external excitation amplitude on the vibration and voltage responses are investigated. It can be concluded that the magnets distance is the main factor affecting the potential energy of the system. There can occur monostable and bistable responses by adjusting the magnets distance, thus effectively improving the energy harvesting characteristics of the PVEH. Compared with the traditional piezoelectric energy harvester with constant cross-section cantilever beam, the proposed PVEH with magnetic stepped variable thickness cantilever beam can emerge obvious nonlinear phenomena and achieve broadband frequency responses by optimizing the structural parameters.
2019, Vol. 40 
