Nonlinear Dynamic Analysis of a Piezoelectric Energy Harvester with Mechanical Plucking Mechanism

In this study, we propose an analytical approach based on the modified differential transform method to investigate the dynamic behavior of a plucking energy harvester. The harvester consists of a piezoelectric cantilever oscillator and a rotating plectrum. The analytical approach provides a closed-form solution that helps determine the starting and ending points of the contact phase between the piezoelectric cantilever and the plectrum. This analytical approach is valuable for simulating complex dynamic interferences in multiple or periodic plucking processes. To evaluate the effects of plucking speed and overlap length of the plectrum on single and periodic plucking, a series of simulations were carried out. The output voltage of the piezoelectric energy harvester increases as the overlap length of the plectrum increases. On the other hand, increasing the plucking speed tends to amplify the magnitude of the contact force while reducing the duration of the contact phase. Therefore, it is crucial to optimize the plucking speed to achieve the maximum linear impulse. For periodic plucking, successful synchronization between the motions of the piezoelectric energy harvester and the rotating plectrum must occur within a limited contact zone. Otherwise, dynamic interferences often cause the plectrum to fail to pluck the energy harvester exactly within the contact zone. Additionally, reducing the plucking speed of the plectrum and increasing the overlap length would be more advantageous for successful periodic-plucking energy harvesting.