Three-dimensional finite element model of a high power, low frequency ring-shell flextensional sonar transducer

Abstract

A three-dimensional finite element model of a high power, low frequency ring-shell flextensional transducer (Sparton of Canada, Ltd. Model 34A0610 (Ref. 1) was developed for use with the ATILA code (Ref. 2). This transducer is to be coupled with an analytical acoustic field description in order to model a dense sonar array of US Navy interest (Ref.3) The three-dimensional model was derived from a two0dimensional model provided by the Naval Undersea Warfare Center (Ref. 4). Two types of finite-element analyses were performed using ATILA: (1) an in-air modal analysis, in which the eigenfrequencies and eigenmodes are computed, and (2) an in-water harmonic analysis, in which the pressure field at a desired driving frequency is computer. The frequency of the ring mode computed for the three-dimensional model in the modal analysis was found to be 5 percent higher than the corresponding value for the two-dimensional model.. From the harmonic analysis, the maximum sound pressure level on the acoustic axis was found to be 4 dB higher than the manufacturer's measured value and is located at exactly the same frequency.