Proceedings ArticleDOI
Tone burst eddy current thermography for estimation of corrosion defects in aircraft components
M. N. Libin,Krishnan Balasubramaniam,C. V. Krishnamurthy,Roger Engelbart +3 more
- Vol. 1430, Iss: 1, pp 425-432
TLDR
In this article, the effect of the parameters affecting the eddy current generation of head in the metal, including excitation frequency, electrical conductivity, standoff distances, etc were considered in optimizing the heat generation.Abstract:
Tone Burst Eddy Current Thermography (TBET) technique was used for the evaluation of corrosion type damage in Aluminum plate like structures. Both flat and curved components were considered. The effect of the parameters affecting the eddy current generation of head in the metal, including excitation frequency, electrical conductivity, standoff distances, etc were considered in optimizing the heat generation. The thermal diffusivity and thickness of the metal structure were considered while selecting the detection of the signal using a thermal sensitive IR Camera. The experiments were conducted using test samples that had simulated defects with different wall thickness losses. The experiments were supported by a multiphysics 3D Finite Element Model (FEM) using COMSOL. The results were compared with the experimental results. It was determined that this technique has some advantages for the inspection aircraft structural components compared to other modalities, particularly in curved regions.read more
Citations
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Journal ArticleDOI
Detection of dis-bond between honeycomb and composite facesheet of an Inner Fixed Structure bond panel of a jet engine nacelle using infrared thermographic techniques
TL;DR: The Inner Fixed Structure (IFS) bond panel is a honeycomb sandwich panel with CFRP facesheet and a heat shield on one side, and a perforated CFRP faceheet on the other side, of a jet engine nacell as mentioned in this paper.
Proceedings ArticleDOI
Scanning induction thermography (SIT) on damaged carbon-fiber reinforced plastics (CFRP) components
TL;DR: In this paper, a scan-induction-thermography (SIT) technique was used to detect impact damage, location of stiffeners and disbonds in Carbon-Fiber Reinforced Plastics (CFRP) components.
References
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Book
Theory and Practice of Infrared Technology for Nondestructive Testing
TL;DR: In this paper, the authors present an active and passive approach to active thermography for nondestructive testing of infrared sensors and Optic Fundamentals using Matlab M-Scripts.
Journal ArticleDOI
Quantitative evaluation of angular defects by pulsed eddy current thermography
TL;DR: In this article, a slope inclination feature of the transient temperature distribution has been extracted and presented for estimating the angle of slots that is independent of slot depth and length inside the sample.
Book
Numerical Modeling for Electromagnetic Non-Destructive Evaluation
TL;DR: In this article, the electromagnetic field equations are solved using the finite element method and the finite difference method of elliptic processes, with boundary integral, volume integral, and combined formulations.
Coil design and fabrication: basic design and modifications
Stanley Zinn,S. L. Semiatin +1 more
Abstract: Basic design considerations The inductor is similar to a transformer primary, and the workpiece is equivalent to the transformer secondary (Fig. 1). Therefore, several of the characteristics of transformers are useful in the development of guidelines for coil design. One of the most important features of transformers is the fact that the efficiency of coupling between the windings is inversely proportional to the square of the distance between them. In addition, the current in the primary of the transformer, multiplied by the number of primary turns, is equal to the current in the secondary, multiplied by the number of secondary turns. Because of these relationships, there are several conditions that should be kept in mind when designing any coil for induction heating: 1) The coil should be coupled to the part as closely as feasible for maximum energy transfer. It is desirable that the largest possible number of magnetic flux lines intersect the workpiece at the area to be heated. The denser the flux at this point, the higher will be the current generated in the part. 2) The greatest number of flux lines in a solenoid coil are toward the center of the coil. The flux lines are concentrated inside the coil, providing the maximum heating rate there. 3) Because the flux is most concentrated close to the coil turns themselves and decreases farther from them, the geometric center of the coil is a weak flux path. Thus, if a part were to be placed off center in a coil, the area closer to the coil turns would intersect a greater number of flux lines and would therefore be heated at a higher rate, whereas the area of the part with less coupling would be heated at a lower rate; the resulting pattern is shown schematically in Fig. 2. This effect is more pronounced in high-frequency induction heating. 4) At the point where the leads and coil join, the magnetic field is weaker; therefore, the magnetic center of the inductor is not necessarily the geometric center. This effect is most apparent in single-turn coils. As the number of coil turns increases and the flux from each turn is added to that from the previous turns, this condition becomes less important. Due to the impracticability of always centering the part in the work coil, the part should be offset slightly toward this area. In addition, the part should be rotated, if practical, to provide uniform exposure.
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