Design for a modular and scalable sonar source using displacement amplifying lamina

Abstract

A sonar sound source is described that is capable of radiating increased sound power at low frequencies in a non-resonant mode of operation. Non-resonant operation is used so that the amplitude and phase of the generated signals are smooth over a range of frequencies. The improvement in output is achieved in part by the use of Galfenol, a fairly new magnetostrictive (MS) material with a high MS strain coefficient. The enhanced output is also due to the use of non-resonant amplifying volume displacing lamina. The system is modeled using a simplified equivalent circuit linear model that allows prediction of several quantities of interest, such as the radiated output, the strain in the MS material, the excitation power, and the sensitivity to ambient pressure fluctuations. [Work supported in part by the US Air Force and the US Navy.]