Low Frequency Eddy Current Detection and Evaluation of Corrosion in Aircraft Skins

摘要

Applicability of low frequency eddy current test for the detection and evaluation of corrosion on aircraft fuselage skins was evaluated with two different commercially available eddy current instruments, one with needle indicator and the other with flying dot CRT display. Experiments carried out on laboratory samples 1.8 mm thick chemically milled to simulated corrosion, show that results are quite good when only 1 sheet is involved and frequencies between 4 and 10 KHz are applied. But when corrosion is under doubler areas the separation between skin and doubler is a major variable in quantitative measurements.