Modeling and Analysis of Piezoelectric Energy Harvesting With Dynamic Plucking Mechanism

Nonharmonic excitations are widely distributed in the environment. They can work as energy sources of vibration energy harvesters for powering wireless electronics. To overcome the narrow bandwidth of linear vibration energy harvesters, plucking piezoelectric energy harvesters have been designed. Plucking piezoelectric energy harvesters can convert sporadic motions into plucking force to excite vibration energy harvesters and achieve broadband performances. Though different kinds of plucking piezoelectric energy harvesters have been designed, the plucking mechanism is not well understood. The simplified models of plucking piezoelectric energy harvesting neglect the dynamic interaction between the plectrum and the piezoelectric beam. This research work is aimed at investigating the plucking mechanism and developing a comprehensive model of plucking piezoelectric energy harvesting. In this paper, the dynamic plucking mechanism is investigated and the Hertzian contact theory is applied. The developed model of plucking piezoelectric energy harvesting accounts for the dynamic interaction between the plectrum and the piezoelectric beam by considering contact theory. Experimental results show that the developed model well predicts the responses of plucking piezoelectric energy harvesters under different plucking velocities and overlap lengths. Parametric studies are conducted on the dimensionless model after choosing appropriate scaling. The influences of plucking velocity and overlap length on energy harvesting performance and energy conversion efficiency are discussed. The comprehensive model helps investigate the characteristics and guide the design of plucking piezoelectric energy harvesters.