Optimization of the pulse-compression technique applied to the infrared thermography nondestructive evaluation

Silipigni, Giuseppe; Burrascano, Pietro; Hutchins, David A.; Laureti, Stefano; Petrucci, Roberto; Senni, Luca; Torre, Luigi; Ricci, Marco

doi:10.1016/j.ndteint.2017.01.011

Cited by 77 publications

(83 citation statements)

References 40 publications

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“…Moreover, based on this preliminary study, the application of quantitative infrared thermography for depth prediction in different materials and/or for the characterisation of different defects would provide a clearer view in the assessment of these depth prediction methods. In this direction, a comparative study incorporating different methodologies for depth prediction, such as the Logarithmic Peak Second-Derivative Time method [41], techniques based on the development of numerical modelling [42], or the recently developed Pulse Compression Thermography [43][44][45], which has shown to provide results with enhanced SNR, can define more representatively the strengths and weaknesses of each quantitative technique. −11.5 …”

Section: Discussionmentioning

confidence: 99%

Depth Retrieval Procedures in Pulsed Thermography: Remarks in Time and Frequency Domain Analyses

Theodorakeas

Koui

2018

Applied Sciences

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Featured Application: The present study intends to show the potentiality of pulsed thermographic imaging to quantitatively characterise hidden defects in Carbon Fibre Reinforced Polymers. By comparing the performance of different depth retrieval procedures, it was possible to evaluate the produced depth estimation accuracy and to define the impact of different experimental and analysis parameters in quantitative analysis. Abstract:In the present study, a Carbon Fibre Reinforced Polymer (CFRP) sample of trapezoid shape, consisting of internal artificial delaminations of various sizes and depth locations, is investigated by means of optical pulsed thermography for the retrieval of quantitative depth information. The main objectives of this work are to evaluate the produced depth estimation accuracy from two contrast-based depth inversion procedures as well as to correlate the acquired results with characteristics such as the location and size of the detected features and with analysis parameters such as the selection of the sound area. Quantitative analysis is performed in both the temporal and frequency domains, utilising, respectively, the informative parameters of thermal contrast peak slope time and blind frequency. The two depth retrieval procedures are applied for the depth estimation of features ranging in size from 3 mm to 15 mm and in depth from 0.2 mm to 1 mm. The results of the present study showed that the two different analyses provided efficient depth estimations, with frequency domain analysis presenting a greater accuracy. Nevertheless, predicting errors were observed in both cases and the factors responsible for these errors are defined and discussed.

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Section: Discussionmentioning

confidence: 99%

Depth Retrieval Procedures in Pulsed Thermography: Remarks in Time and Frequency Domain Analyses

Theodorakeas

Koui

2018

Applied Sciences

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“…Consequently, ECPT provides a promising technique to detect surface cracks on the matrix of PDC bits. It is noted that the latest development of a novel pulse-compression technique would be very useful for further improvement of the proposed detection technique [23]. In the future, we will conduct a further investigation on improving the detectability of ECPT for the surface defect detection of PDC bits, which mainly focuses on numerical simulation to reveal the optimization mechanisms of detection parameters, designing a new coil with special geometry, and the integration with the novel pulsecompression techniques.…”

Section: Discussionmentioning

confidence: 99%

An Investigation on Eddy Current Pulsed Thermography to Detect Surface Cracks on the Tungsten Carbide Matrix of Polycrystalline Diamond Compact Bit

Gong

Zhang

et al. 2017

Applied Sciences

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Polycrystalline diamond compact (PDC) bits are commonly used drill bits in the petroleum drilling industry. Cracks often occur on the surface of a bit, which may result in the unexpected suspension of the drilling operation, or even accidents. Therefore, the detection of surface cracks on PDC bits is of great importance to ensure continuous drilling operation and to prevent accidents. However, it is extremely difficult to detect such cracks by visual inspection or other traditional nondestructive testing (NDT) techniques due to the small size of cracks and the irregular geometry of bits. As one emerging NDT technique, eddy current pulsed thermography (ECPT) can instantly detect surface cracks on metal parts with irregular geometry. In this study, the feasibility of ECPT of detecting surface cracks on the tungsten carbide matrix of PDC bits was investigated. A successive scanning detection mode is proposed to detect surface cracks by using ECPT with a low power heating excitation unit and small-size coils. The influence of excitation duration on the detection result was also investigated. In addition, principal component analysis (PCA) was employed to process the acquired IR image sequences to improve detection sensitivity. Finally, the whole shape of a crack was restored with processed images containing varied cracks segments. Based on the experimental results, we conclude that the surface cracks on the tungsten carbide matrix of PDC bit can be detected effectively and conveniently by ECPT in scanning mode with the aid of PCA.

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“…Therefore, the so-provided heating stimulus can be modelled as a Dirac's Delta function ( ), and the corresponding output ( ), i.e. the pixel temperature/emissivity amplitude recorded with the elapsing time, is a good approximation of the impulse response ℎ( ) [19]. Features of interest are obtained by analyzing the ℎ( ) within a chosen range of interest ℎ as showed in Fig.3 (b).…”

Section: Pulse Compression Basic Theorymentioning

confidence: 99%

“…In AT, the desired thermal contrast is achieved by applying an external heating stimulus over the SUT [13] by means of various different physical sources. Light sources are the most common, see for instance [14][15][16][17][18][19], the SUT's illuminated surface heats up and then the heat diffuses toward the inner side of the sample to restore thermal equilibrium [20]. Alternatively, other methods of excitation have been proposed and successfully applied such as Ultrasound Vibro-Thermography [21], Eddy-Current Pulsed Thermography (ECPT) [22] and Microwave Thermography [23].…”

Section: Introductionmentioning

confidence: 99%

“…ECPuCT method is firstly applied on the CFRP benchmark sample containing manmade delamination defects at different depths and the raw data in the form of thermograms are acquired, as for block 1. Then a denoising algorithm is applied on each individual pixel's signal to remove noise and a nonlinear fitting function is also exploited to remove the step-heating contribution from the denoised data as explained in [19], see Fig.1 block 2. Then, as showed in block 3, the calculation of the impulse response ℎ( ) is performed by convolving the de-trended signal with a matched filter.…”

Section: Introductionmentioning

confidence: 99%

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New features for delamination depth evaluation in carbon fiber reinforced plastic materials using eddy current pulse-compression thermography

Tian

Malekmohammadi

et al. 2019

NDT & E International

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The growing application of composite materials in aerospace leads to the urgent need of non-destructive testing and evaluation (NDT&E) techniques capable of detecting defects such as impact damage and delamination possibly existing in those materials. Eddy current pulsed thermography is an emerging non-destructive testing (NDT) technique capable of detecting such defects. However, the characterization of delamination within composite materials is difficult to be achieved by a single pulse excitation especially in carbon fiber reinforced plastic materials as the extraction of thermal diffusion in such multi-layered structures is challenging. To cope with this problem, this paper proposes the eddy current pulsecompression thermography (ECPuCT) combining the Barker code modulated eddy current excitation and pulse-compression technique to enhance the capability of characterizing delamination on carbon fiber reinforced plastic materials. Additionally, a thermal pattern enhanced method based on kernel principal component analysis technique is used to locate the delaminated areas. Two features, including a newly proposed crossing point of impulse responses related to defective and non-defective areas and skewness of impulse responses are investigated for delamination depth evaluation. Results show that delamination can be detected within depths ranging from 0.46 mm to 2.30 mm and both the proposed features have a monotonic relationship with delamination depths.

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Optimization of the pulse-compression technique applied to the infrared thermography nondestructive evaluation

Cited by 77 publications

References 40 publications

Depth Retrieval Procedures in Pulsed Thermography: Remarks in Time and Frequency Domain Analyses

Depth Retrieval Procedures in Pulsed Thermography: Remarks in Time and Frequency Domain Analyses

An Investigation on Eddy Current Pulsed Thermography to Detect Surface Cracks on the Tungsten Carbide Matrix of Polycrystalline Diamond Compact Bit

New features for delamination depth evaluation in carbon fiber reinforced plastic materials using eddy current pulse-compression thermography

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