A Thermal Analysis of High-Drive Ring Transducer Elements

Abstract : The increasing demand for high-power, low-cost, compact transducer packages for underwater acoustic applications is leading to concerns of overheating in the active, driving piezoelectric ceramic (lead zirconate titanate) elements and the associated passive materials (epoxies and polyurethanes). Pushing a design to its thermal limits can lead to reduced acoustic performance and reliability, and the literature provides little guidance on coping with thermal issues of piezoelectric ceramics in the design phase. This report presents an analytical modeling effort that addresses the thermal issues resulting from dielectric losses for a compact, high-drive, 31-mode, free-flooded ring transducer. For this transducer, thermal issues-rather than electric field or mechanical stress-proved to be the limiting design concern. With modeling (analytical and finite element) and bench-top testing of components, however, proper materials and configuration parameters are selected and the performance goals are subsequently achieved. The approach addresses both the transient thermal response and the steady-state temperature profile that results from high-power, high-duty-cycle drive. These results may prove useful for other similar designs.