A piezoelectric energy harvester with a dual-stage amplification mechanism for efficient vibration energy conversion

Piezoelectric energy harvesting from structural vibrations offers a promising approach for powering structural health monitoring sensors; however, the energy harvesting efficiency of conventional cantilever-based piezoelectric energy harvesters remains relatively low and falls far short of practical sensor power demands. In this study, a vibration-based piezoelectric energy harvester incorporating piezoelectric stacks and a force amplification frame (FA-C PEH) is proposed. The research procedure begins with an analysis of the operating mechanism of the harvester, followed by the development of a finite element model using COMSOL. A prototype harvester is then fabricated and experimentally tested to validate the numerical model, and a systematic parametric investigation is conducted to evaluate the operational characteristics of the device. The results show that under harmonic excitation with an amplitude of 1 m/s2, the maximum power output reaches 7.83 mW. When the force amplification frame angle lies within the range of 95.5° to 97.5°, the harvester exhibits relatively high energy harvesting efficiency. Under the condition of a fixed total height of the piezoelectric stack, different combinations of piezoelectric layer thickness and layer number correspond to distinct optimal external load resistances, while the peak output power under these optimal resistances varies only slightly. The results demonstrate that the proposed FA-C PEH can achieve stable energy harvesting under low-frequency ambient vibration conditions.