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2021 №01 (06) DOI of Article
10.37434/tdnk2021.01.01
2021 №01 (02)


Technical Diagnostics and Non-Destructive Testing #1, 2021, pp. 3-10

Eddy current monitoring of aluminum alloy degradation during long-term operation of aircraft

V.M. Uchanin1, O.P. Ostash1, S.A. Bychkov2, O.I. Semenets2, V.Ya. Derecha2


1G.V. Karpenko Physico-Mechanical Institute of NASU. 5 Naukova str., 79060, Lviv, Ukraine. E-mail: vuchanin@gmail.com
2Antonov Company. 1 Akademika Tupoleva str., 03062, Kyiv, Ukraine. E-mail: info@antonov.com

The monitoring of aluminum alloy degradation is a very important part in aging aircraft maintenance strategy. Our approach is based on the possibility to fi nd the correlation between the material parameters measurable nondestructively and cyclic crack growth resistance characteristics of evaluated material. It was revealed that specifi c electric conductivity as a structure-sensitive parameter of aluminum alloys measured by eddy current method, can be applied as effective tool for such evaluation. The main advantage of the eddy current method is the possibility to carry out the measurements without direct contact with the inspected surface. From the eddy current method point of view, the aircraft component can be represented by 3 layer object which consists of dielectric protective coating, anticorrosive layer about 0,5 mm thick of pure aluminum cladding and aluminum alloy skin subjected to operational loading. To measure conductivity in this third layer with high lift-off suppression (up to 0.5 mm) a new eddy current conductivity meter of the VEPR-31 type was developed. The correlations between the elongation, fatigue limit and electrical conductivity of degraded D16Т and B95Т1 alloys for different equivalent stresses were obtained. The EC electrical conductivity measurements carried out in real aircraft repair plant conditions in Antonov-12B aircraft (produced in 1966) after long-term service confi rmed the proposed methodology effi ciency. Ref. 27, Fig. 8.
Keywords: aircraft, aluminum alloys, degradation, eddy current method, electrical conductivity, fatigue crack growth resistance

Received: 22.01.2021

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