A novel circumferential eccentric eddy current probe and its application for defect detection of small-diameter tubes

Yang, Qingning; Xie, Shejuan; He, Kun; Chen, Yue E.; Chen, Zhenmao; Uchimoto, Tetsuya; Takagi, Toshiyuki

doi:10.1016/j.sna.2021.113023

Cited by 16 publications

(7 citation statements)

References 47 publications

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“…In addition, it was demonstrated that the orientation can be distinguished from the signal phase. It is advantageous that a bobbin probe, which has a simple structure, is effective because it indicates that probes with a more complicated structure, such as a plus-point probe and other ones proposed in recent studies [20,21], would not be required for the nondestructive inspection of the inner surface of the pipe. In contrast, the results of this study confirmed the difficulty in detecting cracks that appear on the outer surface of the pipe.…”

Section: Discussionmentioning

confidence: 99%

Probe Design for the Eddy Current Inspection of Cooling Tubes in the Blanket of a Fusion DEMO Reactor

KAKO

Tomizawa

et al. 2022

Plasma and Fusion Research

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This study investigated the applicability of eddy current testing (ECT) to the non-destructive inspection of cooling tubes in the blanket of a fusion DEMO reactor. Pipes made of F82H steel with inner and outer diameters of 9.0 and 11.0 mm, respectively, were prepared, and slits imitating cracks were fabricated on the pipe surfaces. ECT was performed using a differential type bobbin probe having one exciting and two detecting coils designed in this study. The results of the inspections and subsequent three-dimensional finite element simulations revealed that a bobbin probe is effective in detecting cracks appearing on the inner surface of a pipe. Moreover, the detectability does not deteriorate significantly when cracks oriented in the circumferential directions are targeted, unlike in the case of ECT of the heat exchanger tubes of the steam generators of the pressurized water reactors. This indicates that a probe with a more complicated structure, such as a plus-point probe, would be unnecessary to detect flaws on the inner surface of a pipe. In contrast, the ECT signals from a non-penetrating slit on the outer surface were buried in noise even though the slit was as deep as 0.9 mm.

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Section: Discussionmentioning

confidence: 99%

Probe Design for the Eddy Current Inspection of Cooling Tubes in the Blanket of a Fusion DEMO Reactor

KAKO

Tomizawa

et al. 2022

Plasma and Fusion Research

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“…An inspection system is also developed based on the homogenous LIT technique for the in-situ inspection of the multi-layered first wall panels in the vacuum vessel (VV) of a Tokamak device [7][8][9] . Moreover, we have developed a laser array spots thermography (LAST) technique for the efficient inspection and evaluation of the surface cracks [10][11][12][13][14][15][16] . The LAST method transforms a laser beam to a matrix of laser spots highly localized nearby the crack and adopts an infrared camera to catch the perturbation of the temperature field due to the crack.…”

Section: Introductionmentioning

confidence: 99%

Studies on the infrared thermography technique for quantitative nondestructive evaluation of surface crack and delamination of multilayer structures

Yang

Liu

et al. 2023

International Conference on Optical and Photonic Engineering (icOPEN 2022)

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In this paper, some researches on the laser infrared thermography (LIT) and the eddy current infrared thermography (ECIT) for quantitative nondestructive testing and evaluation of surface cracks and delamination of multilayer structures are introduced. At first, a laser array spots thermography (LAST) method for inspection of surface cracks in metallic structures is presented. LAST related measurement and image processing methods for inspection and quantitative evaluation of crack profiles are introduced in detail. Second, LIT technique and numerical analysis methods for detection and sizing of interface delamination of multilayer structures are introduced aiming at application to the in-vessel structures of Tokamak fusion reactors, such as the first wall panels of blanket modules. At last, some studies on the quantitative nondestructive evaluation of delamination of thermal barrier coating system of gas turbine blades with ECIT are given. The numerical methods for forward analysis of heat generation and transfer process of infrared thermography, and for inverse analysis of defect size with infrared thermography signals are emphasized in this paper, in addition with experimental validations of both the numerical methods and the new inspection techniques.

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“…The above-mentioned techniques have been widely used in steel pipe inspection, but some of them have inherent limitations, e.g., traditional eddy current can only detect defects in the area under the probe; thus, circumferential and axial scanning are required to achieve full coverage; Some detection techniques, such as magnetic flux leakage and alternating current field measurement (ACFM), are more sensitive to cracks in certain directions. There is an increasing need for electromagnetic NDE methods that can thoroughly detect cracks in arbitrary directions, and many novel techniques have been proposed recently, such as circumferential eccentric eddy current probe [10], the array eddy current testing probe [11], etc. In recent years, the rotating electromagnetic field eddy current (RoFEC) method [12] has emerged as a useful NDE technique for plate-like structures [13] to [15], tubular structures [16] to [18], and welding seams [19] and [20].…”

Section: Introductionmentioning

confidence: 99%

Detection of Outer Wall Defects on Steel Pipe Using an Encircling Rotating Electromagnetic Field Eddy Current (RoFEC) Technique

Yin¹,

Gu²,

Wang³

et al. 2022

sv-jme

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In recent years, the rotating electromagnetic field eddy current (RoFEC) testing technique has attracted widespread attention due to its various advantages for inspecting tubular structures. However, most of the related work was focused on detecting inner wall defects on metal pipes using feed-through probes, which are often not applicable for outer wall defect detection. This work pushes forward the encircling RoFEC technique and demonstrates its feasibility for detecting outer wall defects. First, the basic principle of the encircling RoFEC technique is introduced. A three-dimensional finite element (FE) model was built in COMSOL to analyse the distribution of the rotating electromagnetic field and study the interaction between the defects and eddy currents. The axial component of the resultant magnetic field due to defects was selected as a characteristic signal and obtained from the FE models to study the factors, including pipe tilt, defect circumferential location, defect orientation and defect size, that influence the detection performance. An encircling RoFEC system using a probe with six excitation windings and a single bobbin pickup coil was constructed and used to inspect a steel pipe with one axial and one circumferential defect. The obtained voltage signal due to defects can form a Lissajous pattern in the impedance plane and be used for defect evaluation. The results showed that the encircling RoFEC technique can detect outer wall defects of both orientations and determine the circumferential location of the defect.

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A novel circumferential eccentric eddy current probe and its application for defect detection of small-diameter tubes

Cited by 16 publications

References 47 publications

Probe Design for the Eddy Current Inspection of Cooling Tubes in the Blanket of a Fusion DEMO Reactor

Probe Design for the Eddy Current Inspection of Cooling Tubes in the Blanket of a Fusion DEMO Reactor

Studies on the infrared thermography technique for quantitative nondestructive evaluation of surface crack and delamination of multilayer structures

Detection of Outer Wall Defects on Steel Pipe Using an Encircling Rotating Electromagnetic Field Eddy Current (RoFEC) Technique

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