Impulse Analysis of Ultrasonic Indicia
What I would like to talk about today is essentially a portion of a program that has been sponsored by the AFOSR. The primary objectives of the program are to try and analyze defects associated with fastener holes. These include straight-shank fastener holes, tapered shank fastener holes, and cold-worked holes. The total scope of the program is to try and understand the factors that affect the detection capabilities associated with the fastener hole, both with the fastener in place and with the fastener out (including metallurgical, geometric, and local stresses), and to see if there is some way of characterizing the size, the shape and the orientation of the hole in the hope of differentiating between what might be considered a benign defect versus a critical defect. A benign defect, for example, could be some scratches on the inside of the hole that might not be expected to grow. I say, "would not be expected to grow," because you don't know if they are or not.