by Waleed Al-Ashtari, Matthias Hunstig, Tobias Hemsel, Walter Sextro
Abstract:
A piezoelectric cantilever beam with a tip mass at its free end is a common energy harvester configuration. This article introduces a new principle of designing such a harvester that increases the generated power without changing the resonance frequency of the harvester: the attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the efficient operation frequency. Five set-ups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle: theoretical and experimental results show that magnetically stiffened harvesters have important advantages over conventional set-ups with and without tip mass. They generate more power while only slightly increasing the deflection in the piezoelectric harvester and they can be tuned across a wide range of excitation frequencies.
Reference:
Al-Ashtari, W.; Hunstig, M.; Hemsel, T.; Sextro, W.: Increasing the power of piezoelectric energy harvesters by magnetic stiffening. Journal of Intelligent Material Systems and Structures, volume 24, 2013.
Bibtex Entry:
@ARTICLE{Al-Ashtari2013,
author = {Al-Ashtari, Waleed and Hunstig, Matthias and Hemsel, Tobias and Sextro,
Walter},
title = {Increasing the power of piezoelectric energy harvesters by magnetic
stiffening},
journal = {Journal of Intelligent Material Systems and Structures},
year = {2013},
volume = {24},
pages = {1332-1342},
number = {11},
abstract = {A piezoelectric cantilever beam with a tip mass at its free end is
a common energy harvester configuration. This article introduces
a new principle of designing such a harvester that increases the
generated power without changing the resonance frequency of the harvester:
the attraction force between two permanent magnets is used to add
stiffness to the system. This magnetic stiffening counters the effect
of the tip mass on the efficient operation frequency. Five set-ups
incorporating piezoelectric bimorph cantilevers of the same type
in different mechanical configurations are compared theoretically
and experimentally to investigate the feasibility of this principle:
theoretical and experimental results show that magnetically stiffened
harvesters have important advantages over conventional set-ups with
and without tip mass. They generate more power while only slightly
increasing the deflection in the piezoelectric harvester and they
can be tuned across a wide range of excitation frequencies.},
bdsk-url-1 = {http://jim.sagepub.com/content/24/11/1332.abstract},
bdsk-url-2 = {http://dx.doi.org/10.1177/1045389X13483021},
doi = {10.1177/1045389X13483021},
eprint = {http://jim.sagepub.com/content/24/11/1332.full.pdf+html},
file = {Al-Ashtari2013.pdf:Al-Ashtari2013.pdf:PDF},
timestamp = {2013.09.26},
url = {http://jim.sagepub.com/content/24/11/1332.abstract}
}