Optimum Designs of Piezoelectric Fibers
- Paper number
IAC-06-C2.5.08
- Author
Mr. Yohsuke Nambu, University of Tokyo, Japan
- Coauthor
Prof. Junjiro Onoda, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Mr. Yosuke Izumi, University of Tokyo, Japan
- Year
2006
- Abstract
Active fiber composites (AFC), composites with embedded active fibers such as piezoelectric fibers, are very useful smart structures, because they have anisotropic property, advantage of being more resistant to damage, and less intrusive to structures than common mounted actuators. In the traditional AFC, solid piezoelectric fiber is embedded. This type of AFC needs interdigitated electrodes on the surface of AFC, so that matrix materials have to be only dielectric, and this AFC requires high voltage to be driven fully. To overcome these some defects, hollow fiber and fiber with metallic core have been proposed for advanced AFC. In the advanced AFC, the voltage is applied between outer surface of the fiber and inner surface/metallic core. Hollow fiber and fiber with metallic core can be embedded not only in dielectric matrix, but also in conductive matrix, and can be fully driven by relatively lower voltage. The performance of these fibers depends on the configuration of the fibers such as the ratio of inner radius or core radius to the outer radius of the piezoelectric fiber, which is called as the aspect ratio in this abstract. Therefore it is important to identify the optimal value of aspect ratio for various real applications. This paper is composed of two parts. First, we show the governing equations of the fibers: constitutive equations, equivalent equations, compatibility equations, and the Maxwell equations, and obtain the exact solutions. There have been few researches that treat this problem correctly. We investigate the performance of the piezoelectric fibers based on these solutions. Second, we take up several optimum problems with respect to the aspect ratio of each the hollow fiber and the fiber with metallic core. In this study, the performances of the piezoelectric fibers are estimated under some practical constraints. For instance, one of optimal values of aspect ratio maximizes the force produced by a fiber subjected to the maximum allowance voltage that makes local maximum electric field equal to the coercive electric field at which piezoelectricity vanishes.
- Abstract document
- Manuscript document
IAC-06-C2.5.08.pdf (🔒 authorized access only).
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