Multifrequency eddy current (EC) inspection of layered aluminium aircraft structures to detect and size hidden corrosion

The paper lines out the potential of the eddy current method to detect and evaluate corrosion-induced damage (attenuation of wall thickness) in deeper layers of bonded (glued) aluminium sheets. The task is solved by the use of a multi-frequency eddy current inspection device together with optimized EC parameters and an efficient evaluation algorithm to process the EC data. Information about quantitative extension and amount of residual wall thickness caused by corrosion is indicated.