Aging commercial and U.S. Air Force aircraft are known to develop second-layer cracking around the structural fastener holes. A reliable nondestructive evaluation (NDE) technique is needed to detect these cracks for repair or replacement decision making. The desired inspection mode is to place a probe on the outer surface and perform the inspection through the first layer. Two-dimensional scanning using circumferential scans around the fastener and increments in the radial direction, combined with color imaging of the data, was shown to be useful in discriminating between flaws and structure. For specimens having structural variables typical of aircraft wings and having first- and second-layer thicknesses of 6.4 mm, simulated second-layer cracks with radial lengths of 2.5 and 3.8 mm were readily detectable in configurations having first-layer edges, second-layer edges, and adjacent fasteners.
Detection of second-layer cracks under fasteners using eddy current imaging
Nachweis von Rissen in einer zweiten Schicht unter Befestigern mit Hilfe der Wirbelstrom-Abbildung
1994
6 Seiten, 7 Bilder, 7 Quellen
Conference paper
English
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