Online proceedings - EDA Publishing Association

11-13 May 2011, Aix-en-Provence, France
IV. CONCLUSIONS
A multiphysics finite element model of a PMPG was built
that couples mechanic, piezoelectric and fluidic domains.
The latter is represented by air-film between bottom face of
the proof mass and stationary ground surface. Nonlinear
compressible isothermal Reynolds equation is used to
evaluate counter-reactive pressure force that is generated by
squeezed air-film during operation of the generator.
Numerical dynamic analyses revealed that significant air
damping may be induced under atmospheric pressure
leading to substantial reduction of voltage output,
particularly for air gaps below 100 μm. At gaps below 50
μm (at atmospheric pressure), the generated open circuit
voltage is negligible as the exerted air pressure force is so
Fig. 12. AFM images on PVDF samples: 3D phase identification. high that it suppresses the resonance. In this case only
reduction of ambient pressure below ca. 10 Pa may restore
power generation capability of the PMPG. These results
demonstrate that during design of the device its
configuration has to be tailored so as to minimize
detrimental influence of squeeze-film damping.
Application of PVDF films is planned for fabrication of
the PMPG in the future. This study reported initial results of
experimental characterization of morphology and
crystallinity of the produced polymer films with thickness
of 10 − 20 μm. Application of different analysis techniques
revealed that α phase dominates in all the samples.
ACKNOWLEDGMENT
This research was performed under postdoctoral
fellowship, which is funded by EU Structural Funds project
“Postdoctoral Fellowship Implementation in Lithuania”.
Fig. 13. FT-IR absorption spectra of PVDF sample.
Fig. 14. X-ray diffractogram.
REFERENCES
[1] R.J.M. Vullers, R. van Schaijk, I. Doms, C. Van Hoof, R. Mertens,
"Micropower energy harvesting," Solid-State Electron., vol. 53,
pp. 684-693, 2009.
[2] K.A. Cook-Chennault, N. Thambi, A.M. Sastry, "Powering
MEMS portable devices - a review of non-regenerative and
regenerative power supply systems with special emphasis on
piezoelectric energy harvesting systems," Smart Mater. Struct.,
vol. 17, 2008.
[3] A. Khaligh, P. Zeng, C. Zheng, "Kinetic Energy Harvesting Using
Piezoelectric and Electromagnetic Technologies−State of the Art,"
IEEE Trans. Ind. Electron., vol. 53(3), pp. 850-860, 2010.
[4] D. Zhu, M.J. Tudor, S.P. Beeby, "Strategies for increasing the
operating frequency range of vibration energy harvesters: a
review," Meas. Sci. Technol., vol. 21, 2010.
[5] R.M. Lin, W.J. Wang, “Structural Dynamics of Microsystems -
Current State of Research and Future Directions,” Mech. Syst. Sig.
Process., vol. 20, pp. 1015-1043, 2006.
[6] K.S. Breuer, “Chapter 9. Lubrication in MEMS,” in The MEMS
Handbook, M. Gad-el-Hak, ed. CRC Press, 2002.
[7] T. Veijola, H. Kuisma, and J. Lahdenperä, “The influence of gassurface
interaction on gas film damping in a silicon
accelerometer,” Sens. Actuators, A, vol. A66, pp. 83-92, 1998.
[8] J. Inderherbergh, "Polyvinylidene fluoride (PVDF) appearance,
general properties and processing," Ferroelectrics, vol. 115, pp.
295-302, 1991.
[9] R. Gregorio, "Determination of the alpha, beta, and gamma
crystalline phases of poly(vinylidene fluoride) films prepared at
different conditions," J. Appl. Polym. Sci., vol. 100(4), pp. 3272-
3279, 2006.
[10] V. Sencadas, R.G. Filho, "Processing and characterization of a
novel nonporous poly(vinilidene fluoride) films in the beta phase,"
J. Non-Cryst. Solids, vol. 352, pp. 2226-2229, 2006.
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