New transduction materials and their application in sonar transducers

Piezoelectric ceramic-polymer composites having connectivity patterns of both the 0-3 and the 1-3 types were investigated for applications in the development of large-area hydrophones for future hull-mounted conformal sonar arrays. The ceramic phase included the conventional lead zirconate titanate and new lead titanates. Different epoxy and polyurethane resins, as well as conventional neoprene rubber, have been used as the polymer phase in the composites. Prototype hydrophones as large as 15 cm*15 cm were fabricated and incorporated into small arrays for the evaluation of their acoustical performance. The free-field voltage sensitivities of these large-area hydrophones were found to be satisfactory for sonar applications over a broad acoustic frequency range. The performance of composite hydrophones was also shown to be independent of pressure up to at least 20 MPa. The advantages of using these composite materials in meeting the design requirements of affordable and reliable large conformal arrays are also discussed.<>