Piezomagnetoelastic energy harvesting from vortex-induced vibrations using monostable characteristics

The concept of harvesting energy from vortex-induced vibrations (VIVs) by introducing nonlinear attractive magnetic forces is proposed and investigated for the first time. The objective is to design broadband synchronization regions for efficient piezoelectric energy harvesting from VIVs of circular cylinders. A lumped-parameter model is constructed by coupling the dynamics of the energy harvesting system subjected to VIV with the generated voltage across the electrical load resistance. A modified van der Pol wake oscillator is considered for modeling the vortex-induced fluctuating lift force. The magnetic force representation is based on the dipole-dipole interaction. Firstly, the effects of the spacing distance between the two magnets on the buckling configuration of the energy harvester is studied through a static analysis. Then, a linear analysis is performed to determine the impacts of the spacing distance on the natural frequency and damping ratio of the energy harvester in the monostable configuration. A nonlinear dynamic analysis is carried out to determine the impacts of the spacing distance and electrical load resistance on the output performance of the harvester in terms of the synchronization region and levels of the harvested power. The results show that changing the spacing distance produces a variation of the natural frequency and hence a shift of the lock-in region, which is significant for low wind speed energy harvesting. Furthermore, it is demonstrated that depending on the available wind speed in the environment, the spacing distance and load resistance can be adjusted for efficient and broadband energy harvesting from VIV.