Introducing hinge mechanisms to one compressive-mode piezoelectric energy harvester

In this paper, a hinge mechanism is introduced into one compressive-mode piezoelectric energy harvester to improve its performance. First, the concept of implementing hinge mechanisms is introduced on a high-efficiency compressive-mode piezoelectric energy harvester (HC-PEH). Second, a numerical model based on the piezoelectric constitutive equation and the Duffing oscillator equations is formulated to obtain voltage responses, velocity responses, and the fundamental frequency and bandwidth. Then, a prototype is fabricated to validate the results of the model. Depending on the number of hinges applied to the HC-PEH, three cases are investigated: fully hinged, partially hinged, and clamped. In both numerical modeling and experimental studies, the HC-PEH prototypes in the three cases are exposed to frequency-sweep excitations to illustrate the dynamic and transduction behaviors. The results demonstrate that the overall performance in the hinged cases is improved significantly compared to that in the clamped case. The output voltage and output power are increased by 2–3 times and up to 5 times, respectively, and fundamental resonant frequency is lowered to below 20 Hz. Furthermore, it is shown that the operational bandwidth is widened by up to 37%.