An improved piezoelectric acoustic emission transducer

Abstract

A piezoelectric transducer has been designed and developed that has promise of being a high fidelity acoustic emission (AE) transducer [T. M. Proctor, Jr., J. Acoust. Soc. Am. Suppl. 1 68, S568 (1980)]. Small transducer contact area, elimination of acoustical interference effects associated with certain geometries, and redistribution of the arrival times of reflected signals originating from various elements of the transducer were the guiding criteria in the design. This transducer consists of a conical active element and an extended backing. The transducer’s performance has been compared to a line capacitance transducer using surface wave signals. These comparisons indicate an amplitude response which is flat within ±3 dB for the frequency range of 50 kHz to 1 MHz. The over-all displacement sensitivity is nominally 2×108 V/m. Factors that influence frequency response such as backing geometry and aperture size have been experimentally investigated and results are reported.