A REVIEW ON EDDY CURRENT THERMOGRAPHY TECHNIQUE FOR NON-DESTRUCTIVE TESTING APPLICATION

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
N. S. Rusli ◽  
I. Z. Abidin ◽  
S. A. Aziz

Eddy current thermography is one of the non-destructive testing techniques that provide advantages over other active thermography techniques in defect detection and analysis. The method of defect detection in eddy current thermography has become reliable due to its mode of interactions i.e. eddy current heating and heat diffusion, acquired via an infrared camera. Such ability has given the technique the advantages for non-destructive testing applications. The experimental parameters and settings which contribute towards optimum heating and defect detection capability have always been the focus of research associated with the technique. In addition, the knowledge and understanding of the characteristics heat distribution surrounding a defect is an important factor for successful inspection results. Thus, the quantitative characterisation of defect by this technique is possible compared to the conventional non-destructive which only acquired qualitative result. In this paper, a review of the eddy current thermography technique is presented which covers the physical principles of the technique, associated systems and its applications. Works on the application of the technique have been presented and discussed which demonstrates the ability of eddy current thermography for non-destructive testing of conductive materials.   

2021 ◽  
Vol 11 (3) ◽  
pp. 1003
Author(s):  
Christoph Tuschl ◽  
Beate Oswald-Tranta ◽  
Sven Eck

Inductive thermography is a non-destructive testing method, whereby the specimen is slightly heated with a short heating pulse (0.1–1 s) and the temperature change on the surface is recorded with an infrared (IR) camera. Eddy current is induced by means of high frequency (HF) magnetic field in the surface ‘skin’ of the specimen. Since surface cracks disturb the eddy current distribution and the heat diffusion, they become visible in the IR images. Head checks and squats are specific types of damage in railway rails related to rolling contact fatigue (RCF). Inductive thermography can be excellently used to detect head checks and squats on rails, and the method is also applicable for characterizing individual cracks as well as crack networks. Several rail pieces with head checks, with artificial electrical discharge-machining (EDM)-cuts and with a squat defect were inspected using inductive thermography. Aiming towards rail inspection of the track, 1 m long rail pieces were inspected in two different ways: first via a ‘stop-and-go’ technique, through which their subsequent images are merged together into a panorama image, and secondly via scanning during a continuous movement of the rail. The advantages and disadvantages of both methods are compared and analyzed. Special image processing tools were developed to automatically fully characterize the rail defects (average crack angle, distance between cracks and average crack length) in the recorded IR images. Additionally, finite element simulations were used to investigate the effect of the measurement setup and of the crack parameters, in order to optimize the experiments.


2022 ◽  
Vol 1049 ◽  
pp. 282-288
Author(s):  
S.F. Dmitriev ◽  
Vladimir Malikov ◽  
Alexey Ishkov ◽  
Sergey Voinash ◽  
Marat Kalimullin ◽  
...  

This research is devoted to the application of non-destructive testing methods for detecting defects of the internal structure of the material in steel pipelines. Despite the use of modern approaches to the design and manufacture of pipelines, which make it possible to lay a significant margin of safety in the created system, the task of developing new approaches to measuring the technical and operational characteristics and parameters of steel parts using software and hardware complexes for non-destructive testing does not lose its relevance. The paper presents the results of the development of defect detection system aimed at detecting damage of the structure of the material with a diameter of 0.2 mm and located at a depth of up to 2 mm. The proposed system is based on the physical principles of the influence of the existing defect on the value of the transformer voltage, which is induced in the measurement circuit of the sensor built on eddy current effects. The focus of the research is the relationship between the linear dimensions of the defect, its location and the generated voltage indications of the developed sensor. Also, within the framework of the study, the results of processing and analysis of the data collected by the defect detection system are presented, the result of which was the determination of the parameters of the detected defects.


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