Ultrasonic Detection of Embedded and Surface Defects in Thin Plates Using Lamb Waves

摘要

Assuming the resolution of a signal processing system can distinguish reflection coefficients greater than 10% from background noise, it is clear that all widths of defect studied could be potentially detected. Difficulties might occur in that a given reflection coefficient for a particular frequency input could correspond to one of two defect widths (or, in general, to a different height width combination). It should be possible to overcome this difficulty by evaluating the behaviour of a range of frequencies, and combining the information from each component to develop a signature for the defect. For surface defects, it would be more straightforward to determine defect depth, though there would be very little information on defect width.