Thomas R. Howarth
Kurt M. Rittenmyer
Robert Y. Ting
Naval Res. Lab., Underwater Sound Reference Detachment, P.O. Box 568337, Orlando, FL 32856-8337
Two 1--3 piezocomposite rings have been recently electroacoustically evaluated for sonar application. The two rings have outer diameters of 345 mm, 101.6-mm height and a wall thickness of 5 mm. Both have a 5% Navy type II piezoceramic volume concentration loading. The host epoxy of one ring is soft while the other is hard. Both rings had 17.78 by 25.4 mm rectangular elements etched into a 3 by 3 element pattern in their outer electrode for direct in-water performance comparison with a previous design utilizing individual elements of the same dimensions [Howarth et al., J. Acoust. Soc. Am. 91, 2325--2326 (A) (1992)]. The in-water measurements include wide-band free-field voltage sensitivity (FFVS), transmitting voltage response (TVR), and radiation patterns in both the XY and XZ planes. A laser Doppler vibrometry was used for in-air evaluation of the piezoelectric charge constant and surface displacement. Interelement coupling data will also be presented. [Work sponsored by the Office of Naval Research.]