An onionskin composite as a transducer backing material

Abstract

This paper describes the use of an onionskin composite for the backing material of piezoceramic elements in a high-frequency transducer array. It is the purpose of this paper to cite certain advantages of using this particular composite over a more rigid type material. Measurements on experimental test arrays consisted of single-stave directivity patterns and receiving sensitivity versus hydrostatic pressure. In order to show that a sonar array performance can be affected by the piezoceramic backing material, calculated array pattern data, based upon measured and calculated single-stave patterns, are presented in tabular form. The fabrication technique of putting the onionskin on a curved-face housing is presented. In the process, the composite is precompressed such that after being potted in polyurethane, the array will withstand high hydrostatic pressures without an extreme degradation in the sound isolating, tuning, and reflecting properties of the array.