A comparison of high-performance acoustic emission transducers

The constructions of a capacitive (C) transducer, an improved wide-band PZT transducer and two PVDF transducers are presented. For calibration purposes, the breaking of a brittle capillary tube on a steel plate is applied. The responses of the transducers to displacement in the epicenter of the source on a steel plate show that the signals from the capacitive (C) and PZT transducers represent displacement, while the signal from the PVDF transducer represents velocity. The sensitivities of the transducers are characterized by transient response functions calculated by deconvolution of the measured signals and a theoretically determined plate response function. C, PZT and larger PVDF transducers are of comparable performance, while the miniature PVDF transducer is inferior due to its much smaller sensitivity.