Low-Profile, Broadband, Shear-Mode SONAR Transducer for Deep Submergence Applications

Hadal Inc. is partnering with the Pennsylvania State University through its Applied Research Laboratory (PSU:ARL) to develop a 6000 depth rated d36-based shear mode transducer. The combined experience provides an opportunity to develop and test a single crystal projector for incorporation into Navy and commercial systems. The discovery of a large longitudinal (d36) shear coefficient in piezo-crystals has lead to a novel transducer design previously unattainable with conventional piezo-ceramic. This crystal cut allows the working electrodes to be the same as the poling electrodes so that large driving electric fields can be applied without depoling. The electromechanical properties surpass traditional 33 mode crystal cuts. Measured d36 coefficients in the PMNT and PIMNT systems exceed 2200 pm/V and k36 values are greater than 0.80. This cut also has an extraordinarily high elastic compliance greater than 190 x 10-12 m2/N and a mechanical Q over 800. These characteristics are ideal for compact, high power, broadband acoustic projectors. Phase I suggested it was possible to build a compact shear mode transducer that operates at 10,000 psi ambient pressures. The design utilizes a two-stage isolation mount, housing, and fairing. Further investigation into a suitable pressure housing, fairing, and modified shear transducer is required.