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Bimorph

About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.


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Journal ArticleDOI
TL;DR: In this article, the shape of scavengers is optimized to increase the specific power generated per unit of scavenger volume by optimizing shape of the scavengers, and two optimized trapezoidal configurations are identified and analyzed.
Abstract: Compact autonomous power sources are one of the prerequisites for the development of wireless sensor networks. In this work vibration energy harvesting via piezoelectric resonant bimorph beams is studied. The available analytical approaches for the modeling of the coupled electromechanical behavior are critically evaluated and compared with a finite element (FEM) numerical model. The latter is applied to analyze thoroughly the stress and strain states, as well as to evaluate the resulting voltage and charge distributions in the piezoelectric layers. The aim of increasing the specific power generated per unit of scavenger volume is pursued by optimizing the shape of the scavengers. Two optimized trapezoidal configurations are hence identified and analyzed. An experimental set-up for the validation of the proposed numerical model and of the obtained optimized structures is developed. Results of a preliminary experimental assessment, confirming the improved performances of optimized scavengers, are finally given.

177 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a frequency up-conversion strategy for a new piezoelectric wearable energy harvester to reduce the battery burden on people, where the pluck-based frequency upconversion is obtained by deflecting the bimorph via a plectrum, then rapidly releasing it so that it can vibrate unhindered; during the following oscillatory cycles, part of the mechanical energy is converted into electrical energy.
Abstract: The modern drive towards mobility and wireless devices is motivating intensive research in energy harvesting technologies. To reduce the battery burden on people, we propose the adoption of a frequency up-conversion strategy for a new piezoelectric wearable energy harvester. Frequency up-conversion increases efficiency because the piezoelectric devices are permitted to vibrate at resonance even if the input excitation occurs at much lower frequency. Mechanical plucking-based frequency up-conversion is obtained by deflecting the piezoelectric bimorph via a plectrum, then rapidly releasing it so that it can vibrate unhindered; during the following oscillatory cycles, part of the mechanical energy is converted into electrical energy. In order to guide the design of such a harvester, we have modelled with finite element methods the response and power generation of a piezoelectric bimorph while it is plucked. The model permits the analysis of the effects of the speed of deflection as well as the prediction of the energy produced and its dependence on the electrical load. An experimental rig has been set up to observe the response of the bimorph in the harvester. A PZT-5H bimorph was used for the experiments. Measurements of tip velocity, voltage output and energy dissipated across a resistor are reported. Comparisons of the experimental results with the model predictions are very successful and prove the validity of the model.

175 citations

Journal ArticleDOI
TL;DR: A novel graphene-on-organic film fabrication method that is compatible with a batch microfabrication process was developed and used for electromechanically driven microactuators, enabling the successful demonstration of transparent graphene-based organic microactsuators.
Abstract: A novel graphene-on-organic film fabrication method that is compatible with a batch microfabrication process was developed and used for electromechanically driven microactuators. A very thin layer of graphene sheets was monolithically integrated and the unique material characteristics of graphene including negative thermal expansion and high electrical conductivity were exploited to produce a bimorph actuation. A large displacement with rapid response was observed while maintaining the low power consumption. This enabled the successful demonstration of transparent graphene-based organic microactuators.

163 citations

Journal ArticleDOI
TL;DR: In this article, the dynamic and energy properties of a multi-stable bimorph cantilever energy harvester with magnetic attraction effect have been investigated and the mechanism that governs the formation of this multi-stability is thoroughly identified and examined thorough a bifurcation analysis performed on the system's equilibrium solutions.

159 citations

Journal ArticleDOI
TL;DR: In this article, the authors reported the implementation of ultrathin (100 nm) aluminum nitride (AlN) piezoelectric layers for the fabrication of vertically deflecting nanoactuators.
Abstract: This letter reports the implementation of ultrathin (100 nm) aluminum nitride (AlN) piezoelectric layers for the fabrication of vertically deflecting nanoactuators. The films exhibit an average piezoelectric coefficient (d31∼−1.9 pC/N), which is comparable to its microscale counterpart. This allows vertical deflections as large as 40 nm from 18 μm long and 350 nm thick multilayer cantilever bimorph beams with 2 V actuation. Furthermore, in-plane stress and stress gradients have been simultaneously controlled. The films exhibit leakage currents lower than 2 nA/cm2 at 1 V, and have an average relative dielectric constant of approximately 9.2 (as in thicker films). These material characteristics and actuation results make the AlN nanofilms ideal candidates for the realization of nanoelectromechanical switches for low power logic applications.

152 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202358
2022116
202191
202090
2019123
2018117