Stress-Dependent Behavior of d33 and Y in Navy Types III and VI Ceramics E 33

Abstract

The stress dependence of hard and soft active ceramic properties is important because many submarine sonar transducers are subject to compressive mechanical prestress as well as dynamic stress variations caused by ac electrical excitation. The level of prestress to which a ceramic in a transducer is subjected also depends in part on operational factors, such as the level of ac activation and depth of the submersible. This investigation builds upon prior work (Yang, G., Liu, S-F., Ren, W. and Mukherjee, B.K. 2000. “Uniaxial Stress Dependence of the Piezoelectric Properties of Lead Zirconate Titanate Ceramics,” Smart Structures and Materials 2000: Active Materials: Behavior and Mechanics, Proceedings of SPIE, Vol. 3992, pp. 103-113.) by examining the time dependence and the uniaxial stress dependence of the average, differential and dynamic d₃₃ and Y^E ₃₃ of Navy Type III (PZT8) and Navy Type VI (PZT5H) lead zirconate titanate ceramics. This research incorporates higher levels of prestress and various mid-level ac stress cycles. Under short-circuit conditions, large and small compressive stresses are applied while measuring dielectric displacement and strain. The piezoelectric coefficient, d₃₃, is evaluated using the direct method as a function of time, prestress level, and ac stress magnitude. The constant-field modulus is calculated from the slope of the corresponding stress-strain curves. Intrinsic and extrinsic contributions to these properties are discussed.