2021 №04 (06) DOI of Article
2021 №04 (02)

Technical Diagnostics and Non-Destructive Testing 2021 #04
Technical Diagnostics and Non-Destructive Testing #4, 2021, pp. 11-18

Application of Hilbert transform for analysis of signals of automated eddy current inspection. Part 2. Deriving secondary diagnostic features and examples of realization

Yu.V. Kuts1, V.M. Uchanin2, Yu.Yu. Lysenko1, V.F. Petryk1, O.E. Levchenko1, G.A. Bogdan1

1National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute». 37 Peremohy Sve., 03056, Kyiv, Ukraine. E-mail: y.kuts@ukr.net
2G.V.Karpenko Physico-Mechanical Institute of NASU. 5 Naukova Str., 79060, Lviv, Ukraine. E-mail: vuchanin@gmail.com

In the first part of the paper it was shown that the discrete Hilbert transform of eddy current control signals allows obtaining samples of discrete characteristics of these signals. The second part deals with application of these data to derive the deterministic and statistical characteristics – the laws of modulation of the amplitude and phase of the signals and round robin statistics, obtained from the difference in phase characteristics of the signals. The paper is devoted to investigations of application of phase methods of processing signals of eddy current transducers, which are based on a combination of discrete Hilbert transform and methods of deterministic and statistical measurement of the phase. The paper gives examples of application of secondary diagnostic features, derived by phase characteristic of the signals to solve the problems of automated eddy current control. An experimental diagnostic system of eddy current control was developed, which uses the frequency of natural oscillations of the transducer signal as an information parameter. The proposed system envisages transducer application in the oscillation mode, both of absolute type and double differentiation transducers. Analysis of experimental results is given and dependencies were derived by the proposed procedure at defect detection and determination of the thicknesses of the dielectric coating. 10 Ref., 1 Tabl., 11 Fig.
Keywords: eddy current nondestructive testing, discrete Hilbert transformation, phase characteristic of the signal

Received: 08.11.2021


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