Interference of corner reflected and edge diffracted signals for a surface-breaking crack

Backscatter of time-harmonic longitudinal waves from a surface-breaking crack is investigated in the highfrequency range. It is assumed that the distance of the transducer to the crack is large as compared to the crack depth, and that the incident rays are normal to the crack edge. The crack length is assumed much greater than its depth. A two-dimensional model for the transducer is considered. In the time domain, the first and second received signals are the edge-diffracted signal and the comer-reflected signal, respectively. These signals are analyzed in the frequency domain, by using the uniform asymptotic theory of diffraction. The response of the transducer due to the interference of the two signals is calculated. It is shown that the transducer's response is a sensitive function of its position.