Passive frequency tuning and dynamic analysis of an extended simply supported beam piezoelectric energy harvester under rotational excitations

An extended simply supported beam piezoelectric energy harvester (PEH) is proposed in this paper. The proposed configuration features a small tip displacement and exploits centrifugal softening to achieve passive frequency tuning for low-speed applications. A theoretical model is developed to analyze the PEH under base and rotational excitations. The effects of the tip mass, the length of the extended beam, and the distance between the PEH and the rotating center are tested experimentally. The experimental results demonstrate that the proposed configuration provides a more uniform strain distribution over the piezoelectric layer. Compared with related designs reported in the literature, the ESSB-PEH achieves a superior power density of 12.5 μ W/mm 3 at 10 Hz. Furthermore, for a given PEH dimension, positioning the PEH closer to the rotation center increases the resonant frequency and enhances the output voltage. In conclusion, the developed theoretical model provides a foundation for vibration control and performance improvement of piezoelectric energy harvesters in rotational environments, offering insights for the design of more efficient and controllable energy harvesting systems.