scholarly journals Investigation of layer interface model of multi-layer structure using semi-analytical and FEM analysis for eddy current pulsed thermography

Author(s):  
Qiuji Yi ◽  
GuiYun Tian ◽  
Houssem Chebbi ◽  
Denis Premel
2021 ◽  
Vol 282 ◽  
pp. 122642 ◽  
Author(s):  
Jing Xie ◽  
Changwei Wu ◽  
Lemei Gao ◽  
Changhang Xu ◽  
Yinsheng Xu ◽  
...  

2017 ◽  
Author(s):  
Jianping Peng ◽  
Kang Zhang ◽  
Kai Yang ◽  
Zhu He ◽  
Yu Zhang ◽  
...  

2015 ◽  
Vol 742 ◽  
pp. 128-131 ◽  
Author(s):  
Jian Min Zhou ◽  
Jun Yang ◽  
Qi Wan

This paper introduces the theory of eddy current pulsed thermography and expounds the research status of eddy current pulsed thermography in application and information extraction. Thermographic signal reconstruction, pulsed phase thermography, principal component analysis were introuduced in this paper and listed some fusion multiple methods to acquire information from infrared image. At last, it summarizes research progress, existing problem and deelopment of eddy current pulsed thermography.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xiang Zhang ◽  
Jianping Peng ◽  
Luquan Du ◽  
Jie Bai ◽  
Lingfan Feng ◽  
...  

Microcracks are a common metallic defect, resulting in degradation of material properties. In this paper, specimens with different fatigue microcracks were detected by eddy current pulsed thermography (ECPT). Signal processing algorithms were investigated to improve the detectability and sensitivity; principal component analysis (PCA) and Tucker decomposition were used to compare the performance of microcrack detection. It was found that both algorithms were highly adaptable. A thermal quotient was used to assess the temperature variation trend. Furthermore, the potential correspondence between crack closure and temperature change was investigated.


Author(s):  
Jiabin Yang ◽  
Chao Li ◽  
Mengyuan Tian ◽  
Shuyu Liu ◽  
Boyang Shen ◽  
...  

AbstractThe conductor on round core (CORC) cable wound with second-generation high-temperature superconducting (HTS) tapes is a promising cable candidate with superiority in current capacity and mechanical strength. The composing superconductors and the former are tightly assembled, resulting in a strong electro-magnetic interaction between them. Correspondingly, the AC loss is influenced by the cable structure. In this paper, a 3D finite-element model of the CORC cable is first built, and it includes the complex geometry, the angular dependence of critical current and the periodic settings. The modelling is verified by the measurements conducted for the transport loss of a two-layer CORC cable. Subsequently, the simulated results show that the primary transport loss shifts from the former to the superconductors as the current increases. Meanwhile, the loss exhibited in the outer layer is larger than that of the inner layer, which is caused by the shielding effect among layers and the former. This also leads to the current inhomogeneity in CORC cables. In contrast with the two-layer case, the simulated single-layer structure indicates stronger frequency dependence because the eddy current loss in the copper former is always dominant without the cancellation of the opposite-wound layers. The core eddy current of the single structure is denser on the outer surface. Finally, the AC transport losses among a straight HTS tape, a two-layer cable and a single-layer cable are compared. The two-layer structure is confirmed to minimise the loss, meaning an even-numbered arrangement makes better use of the cable space and superconducting materials. Having illustrated the electro-magnetic behaviour inside the CORC cable, this work is an essential reference for the structure design of CORC cables.


Author(s):  
Claudia Rinaldi ◽  
Letizia de Maria ◽  
Federico Cernuschi ◽  
Giampiero Antonelli

The components of the hot gas path in gas turbines can survive to very high temperatures because they are protected by ceramic Thermal Barrier Coatings (TBC); the failure of such coatings can dramatically reduce the component life. A reliable assessment of the Coating integrity and/or an Incipient TBC Damage Detection can help both in optimising the inspection intervals and in finding the appropriate remedial actions. In this paper the potential of three different NDT techniques applicable to the metallo/ceramic coatings of hot parts are discussed in the light of both results obtained on laboratory aged specimens and in field measurements on operated components. An investigation of the NDTs capability to detect damage evolution was performed on thermal-cycled specimens coated with TBC (both EB-PVD and pseudocolumnar APS) by means of an F-SECT eddy current system, by an innovative portable Piezospectroscopic system and by pulsed thermography. The observation of metallographic sections of the thermal cycled specimens allowed to give the right interpretation to the results of each NDT methodology and enlightened its specific characteristics and potentiality. Moreover in field applicability is discussed for each technique. Finally it is shown how an integrated approach of suitable coating evolution models and complimentary NDT techniques can provide an interesting assessment of the damage level of the metallo/ceramic coatings of operated rotating blades.


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