Abstract
Aiming toward improved energy conversion in piezoelectric energy harvesters, this study investigates four-point bending (FPB) energy harvesters (FPB-EH) to explore their prominent features and characteristics. The FPB configuration innovatively extends energy harvesting capabilities relative to conventional cantilever beams. The FPB-EH comprises a composite piezoelectric beam that rests on two supports of a fixed clamp, excited by contact force applied at two contact lines on a moving clamp. A comprehensive analytical electromechanical model for the vibrating energy harvester is presented with unique modeling features, including multi-beam sections and multi-mode-shape functions. Solutions of the analytical model are presented for a wide range of contact force types, including steady-state solutions for harmonic forces, impact forces, periodic and non-periodic arbitrary forces. This comprehensive model progresses the state-of-the-art piezoelectric modeling knowledge and is readily applicable to various energy harvesting configurations. The model is validated against experimental results and finite element analysis. Next, a parametric study was performed to evaluate the effects of various FPB characteristics, including the fixed and moving clamp spans, the waveform, and the period-time of contact force. The results indicate that the FPB configuration can enhance energy conversion efficiency and normalized output energy by factors of over 3 and 6, respectively. Finally, guidance is given for selecting between cantilever and four-point bending configurations.
Original language | English |
---|---|
Article number | 121461 |
Journal | Applied Energy |
Volume | 347 |
ISSN | 0306-2619 |
DOIs | |
Publication status | Published - 1 Oct 2023 |
Bibliographical note
Funding Information:This work is supported by a research grant from the Lundbeck, LF-Experiment grant, under grant number R324-2019-1747. Moreover, this research is partially financed by the Independent Research Fund Denmark International Post-doc grant under grant number 1031-00001B, and Danish Cardiovascular Academy, which is funded by the Novo Nordisk Foundation, grant number NNF20SA0067242, and Danish Heart Foundation.
Publisher Copyright:
© 2023 The Author(s)
Keywords
- Ambient vibration
- Energy conversion efficiency
- Impact excitation
- Piezoelectric energy harvesting