The Paton Welding Journal, 2022, №05



2022 №05 (06)

DOI of Article 10.37434/tpwj2022.05.07

2022 №05 (01)

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The Paton Welding Journal, 2022, #5, 46-50 pages

Study of eddy current flaw detector based on double-circuit self-generator operated in intermittent oscillating mode

V.M. Uchanin

G.V. Karpenko Physico-Mechanical Institute of NASU 5 Naukova Str., 79060, Lviv, Ukraine

Abstract
Timely application of nondestructive methods for testing critical structures of modern engineering is an important factor ensuring their safe and trouble-free operation. Eddy current testing means have no alternative for contactless detection of cracks in aircraft structures. In order to detect surface cracks (also through a layer of dielectric coating), self-generator eddy current flaw detectors are used, working at operating frequencies above 1 MHz. To develop such flaw detectors, it is promising to use double- circuit self-generator oscillatory system, operating in intermittent oscillatory mode. This work is a study of new technical solutions, in particular self-generator circuit based on a field transistor with insulated gate, circuit of controlling the generation frequency and circuit of regeneration of self-generator oscillations. Their advantages in terms of sensitivity are shown, compared to traditional circuits. The analyzed engineering solutions were used to develop self-generator eddy current flaw detectors of VD 3.03N, VD 3.02N, VD 4.01N and VD 4.03N type for surface crack detection, which have passed state testing and are widely used, in particular for maintenance of SC “Antonov” aircraft and SC “Ivchenko-Progress” and PJSC “Motor-Sich” aircraft engines. It is intended to apply these engineering solutions in the new self-generator flaw detector with functions of automatic adjustment for the level of sensitivity and its indication set by the specified procedure.
Keywords: eddy current nondestructive testing, self-generator eddy current flaw detector, surface cracks, intermittent generation, double-circuit, oscillation regeneration

Received: 27.03.2022
Accepted: 08.08.2022

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