Underwater evaluation of piezocomposite panels as active surfaces

A new class of composite materials designated as the 1-3 piezocomposite is being investigated for potential use in underwater smart material structures. In-water acoustical properties of new 1-3 composite panels were examined experimentally as a function of temperature, pressure and frequency. The measured transmitting voltage response (TVR) showed the existence of parasitic modes in the composite panel in addition to the expected thickness mode. The effect of underwater explosive shock on the TVR showed no detrimental effects in mechanical structure or acoustical performance of the piezocomposite panel. The free-field voltage sensitivity was constant at -185 dB referenced to 1 volt per micropascal over the testing frequency range. Linearity with electrical drive level and pressure stability of the 1-3 piezocomposites have also been established with the present choice of ceramic-polymer components. These results demonstrated that this new material is potentially used for applications of both large-area actuators and sensors in forming active surfaces of new smart structures.