Modeling and Experimental Evaluation of Antisymmetrical Interdigitated Electrode Piezoelectric Fiber Composites

• Main Authors: Wu, Yu-Chien, 吳雨倩
• Other Authors: Yin, Ching-Chung
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/38849521947270976047

碩士 === 國立交通大學 === 機械工程系所 === 102 === This thesis studies the characteristics of a novel guided wave transducer using numerical investigation and experimental measurement. The acoustic transducer called antisymmetric interdigitated electrode piezoelectric fiber composite (AE-PFC) is formed with a number of unidirectional piezoelectric fibers embedded in epoxy resin and sandwiched between two thin flexible sheets printed with interdigitated electrodes (IDE). The metal stripes of IDE perpendicular to the fibers provide the poling and actuating electric field. Constant wavelength flexural waves can be transmitted if the AE-PFC is adhered to a host plate and exerted by periodic voltages. This study indicates that the AE-PFC can be used as a low-voltage drive guided wave transducer with very good potential in application of structural health monitoring. Numerical exploration benefits the improvement of low-voltage drive capability of AE-PFC. The induced poling electric field intensity increases as decreasing the space between two adjacent electrodes to the electrode width ratio. The intensity of electric field generated by the IDE aligned symmetrically is twice as many as that placed anti-symmetrically. Increasing the dielectric constant of polymer matrix surrounding piezoelectric fibers will improve the homogeneity of electric field. Experimental evidence indicates that the measured acoustic near field transmitted from AE-PFC is approximate to the Fresnel zone formula of a piston transducer. It remains greater than of the influenced zone determined by added mass effect resulted from the transducer on the host plate.