A new technique for the measurement of acoustic emission transients and their relationship to crack propagation

This paper describes a new broad-band approach to the detection of acoustic emission in which a capacitance transducer has been used to record the transient elastic waves generated by crack growth processes as surface displacements. A unique specimen geometry, the 'Yobell' has been developed to reduce interference from internal reflections of the ultrasonic pulse, so that the measured surface displacements can be compared with those calculated for a source buried below the surface of the half-space. A static source model has been used to relate the rise-time and amplitude of transients to the time-scales and magnitudes of incremental crack growth,