Optimization of piezoelectric cantilever energy harvesters including non-linear effects

Patel, R.; McWilliam, S.; Popov, A.A.

Abstract

This paper proposes a versatile non-linear model for predicting piezoelectric energy harvester performance. The presented model includes (i) material non-linearity, for both substrate and piezoelectric layers, and (ii) geometric non-linearity incorporated by assuming inextensibility and accurately representing beam curvature. The addition of a sub-model, which utilizes the transfer matrix method to predict eigenfrequencies and eigenvectors for segmented beams, allows for accurate optimization of piezoelectric layer coverage. A validation of the overall theoretical model is performed through experimental testing on both uniform and non-uniform samples manufactured in-house. For the harvester composition used in this work, the magnitude of material non-linearity exhibited by the piezoelectric layer is 35 times greater than that of the substrate layer. It is also observed that material non-linearity, responsible for reductions in resonant frequency with increases in base acceleration, is dominant over geometric non-linearity for standard piezoelectric harvesting devices. Finally, over the tested range, energy loss due to damping is found to increase in a quasi-linear fashion with base acceleration. During an optimization study on piezoelectric layer coverage, results from the developed model were compared with those from a linear model. Unbiased comparisons between harvesters were realized by using devices with identical natural frequencies—created by adjusting the device substrate thickness. Results from three studies, each with a different assumption on mechanical damping variations, are presented. Findings showed that, depending on damping variation, a non-linear model is essential for such optimization studies with each model predicting vastly differing optimum configurations.

Citation

Patel, R., McWilliam, S., & Popov, A. (2014). Optimization of piezoelectric cantilever energy harvesters including non-linear effects. Smart Materials and Structures, 23(8), Article 085002. https://doi.org/10.1088/0964-1726/23/8/085002

• Journal Article Type: Article
• Acceptance Date: Apr 22, 2014
• Publication Date: Jun 18, 2014
• Deposit Date: Feb 22, 2018
• Publicly Available Date: Feb 22, 2018
• Journal: Smart Materials and Structures
• Print ISSN: 0964-1726
• Electronic ISSN: 1361-665X
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 23
• Issue: 8
• Article Number: 085002
• DOI: https://doi.org/10.1088/0964-1726/23/8/085002
• Keywords: energy harvesting, piezoelectric beam, geometric non-linearity, material non-linearity, coverage optimization, mechanical damping
• Public URL: https://nottingham-repository.worktribe.com/output/730463
• Publisher URL: http://iopscience.iop.org/article/10.1088/0964-1726/23/8/085002/meta
• Additional Information: This is an author-created, un-copyedited version of an article published in Smart Materials and Structures. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.1088/0964-1726/23/8/085002.