Quantification of hidden corrosion in aircraft structures using enhanced D-Sight NDT technique

In this paper, the enhancement of the D-Sight non-destructive testing technique was proposed by enriching it with a possibility of quantification of hidden corrosion typical for metallic fuselages of aircrafts. The proposed approach is based on the developed image processing technique, which allows the quantifying of the spatial dimensions of a corroded area from D-Sight images, which is supported with finite element modeling to achieve information about the depth and degree of corrosion of a given structure. The D-Sight inspections were validated using metrological measurements and the digital image correlation technique to introduce correction factors for the evaluations of dimensions of a corroded area using D-Sight due to overestimations typical of this technique. The performed studies allowed determination of a lower bound of the detectability of hidden corrosion using the D-Sight technique. The proposed enhancements will improve inspections of aircraft structures, where hidden corrosion remains a serious and unsolved problem.