Temperature effects of cement joints in ceramic-stack resonators

A temperature-related performance degradation has been observed in certain sonar transducers that employ ceramic-stack 33-mode resonators that contain joints. This study sought to identify the cause of this performance degradation and to determine resonator design or assembly methods that limit or eliminate this degradation. Experimental and computer modeling results show that the performance degradation is extreme for little or no final stress bias on the resonators and does not appear to be affected by the initial stress bias (the bias during cement curing). The degradation results from a temperature sensitivity of the stiffness of the cement/electrode joints. A high final stress bias of 28 million Pa essentially eliminates the performance degradation.