APPLICATIONS OF THE DIFFRACTION OF ULTRASOUND BY CRACK TIPS

SUMMARY The ultrasonic energy diffracted from the tips of cracks has been used in the sizing and evaluation of defects for some 20 years. Industrial application is now possible by means of the time of flight diffraction (TOFD) technique developed by one of us (MS) at Harwell and the focussing, echodynamic time-of-flight (FET) technique developed by the other authors at the Ecole Centrale. We have recently jointly reviewed progress in this field 1 and this paper presents some of the important developments and outstanding problems highlighted by the review.