High drive and duty cycle characterization of single crystal transducers

Abstract

Previous device demonstrations have clearly illustrated how the larger strain energy density and electromechanical coupling factors of single crystal could be used to increase both the source level and bandwidth of Naval sonar projectors. This paper will report on two experiments that conclusively demonstrate that single crystal transducers can withstand high drive levels, elevated duty cycles and extended lifetimes without a significant degradation of performance. In the first experiment, a twelve-element array of PMN-PT tonpilz transducers was driven at its resonance frequency to achieve an acoustic intensity of 5 W/sq. cm. Over a range of duty cycles up to 40% and operating times of up to 30 minutes, the impedance and acoustic output of this array remained completely stable once equilibrium had been reached. In a second experiment, a single crystal cylinder transducer was driven at its resonance frequency for ten minutes at duty cycles ranging from 10% to nearly CW. A temperature rise of only 10C over the duration of the test at the highest duty cycles was measured, with only a 20% increase in admittance and no change in tuned power factor. Both transducers returned to their original state following these tests. [This work is sponsored by ONR.]