High-fidelity acoustic-emission sensor/preamplifier subsystems: modeling and experiments

A computer model is used to evaluate the suitability of five piezoelectric materials for use in broadband (10 kHz-2 MHz) acoustic-emission (AE) 'point' sensors. The computer model accounts for the effects of the electrical loading of the piezoelectric material by the input impedance of the preamplifier and the mechanical loading by the specimen and backing materials. The model predictions are compared with results of measurements, which are normalized using the NIST Standard Reference Material (SRM) 'conical' transducer. The effects of selecting different piezoelectric materials and transducer configurations are evaluated experimentally and analytically. It is shown that materials exhibiting the highest dielectric constant are best suited for high-performance AE sensor applications.<
>