International Journal of Applied Electromagnetics and Mechanics - Volume 59, issue 4

Authors: Katagiri, Takuya | Sasaki, Kota | Song, Haicheng | Yusa, Noritaka | Hashizume, Hidetoshi

Article Type: Research Article

Abstract: This study discusses the characteristics of a mode converter to generate microwaves in the TE01 mode for the long-range inspection of pipes. Numerical analysis was conducted to evaluate the effect of the pipe diameter and the number of coaxial cables inserted into the pipe on the efficiency of converting microwaves from the coaxial TEM mode to the circular TE01 mode. The results reveal that the most efficient frequency range for TE01 mode propagation strongly depends on the number of cables and pipe diameter. Subsequent experiments were performed using brass pipes with a length of 5 m and diameters …of 39.0 and 74.0 mm. The results of these experiments are consistent with the results of the numerical analysis: the pipe with a diameter of 39.0 mm showed a clear signal from an axial slit 1.5 m away from the mode converter and the pipe with a diameter of 74.0 mm showed almost no difference between signals with or without the slit. Show more

Keywords: Nondestructive testing, axial cracks, TE modes, metal pipe, time of flight

DOI: 10.3233/JAE-171144

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1527-1534, 2019

Authors: Le, Minhhuy | Kim, Jisoo | Kim, Jungmin | Lee, Hoyong | Lee, Jinyi

Article Type: Research Article

Abstract: A moisture separator reheater (MSR) system is installed between the high-pressure and low-pressure steam turbines in a nuclear power plant to increase the heat efficiency of the power plant. Erosion and corrosion of the MSR tubes have threatened the long-term operation of nuclear power plants. Thus a partial saturation eddy current testing (PSECT) method using a bobbin-type integrated Hall sensor array (BIHaS) was proposed in our previous study and it showed good results compared with a conventional PSECT. This paper presents a novel signal processing technique to improve detectability and measurability of electromagnetic testing method using a BIHaS through mitigating …the inherent vibration signal noise between the BIHaS and ferritic stainless steel tubes. Show more

Keywords: Hall sensor array, partial saturation eddy current testing, electromagnetic testing, moisture separator reheater

DOI: 10.3233/JAE-171234

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1535-1542, 2019

Authors: Xu, Zhiyuan | Lin, Zhangpeng | Xiao, Qi

Article Type: Research Article

Abstract: A remote field eddy current (RFEC) probe for in-service inspection of pipe defects is presented. Firstly, based on finite element analysis, the probe is designed with an external and circumferentially aligned structure. Afterwards, the simulation model of RFEC testing for defect detection is established, and the quantitative relations of the inner diameter (ID) and outer diameter (OD) defect depth to the signal features are analysed. Finally, experimental verification is performed. The results show that: (i) the probe signal phase decreases almost linearly with the increase of ID or OD defect depth, which can be used to quantify defect depth; (ii) …the ID or OD defect depth can be quantified respectively, but, due to the different sensitivity to ID and OD defects, it is still hard to quantify the depth when two types of defect exist simultaneously; and (iii) the defect orientation has little effect on the signal phase. Show more

Keywords: Remote field eddy current, defect detection, in-service inspection, probe design, finite element analysis

DOI: 10.3233/JAE-171171

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1543-1551, 2019

Authors: Qiu, Jinxing | Pei, Cuixiang | Liu, Haochen | Chen, Zhenmao

Article Type: Research Article

Abstract: The laser array spots thermography (LAST) is a new fully non-contact and non-destructive method for inspection of surface cracks. In this study, the capability of this method for inspection of surface crack in specimen at elevated temperature is investigated. The temperature distributions in a specimen at different initial temperature are calculated through simulation and measured through experiment, respectively. Both the simulation and experimental results show that the background noise in the temperature distribution will be increased when the initial temperature of the specimen is enlarged. However, with the aid of an image processing method, the surface cracks in the specimen …with initial temperature from 303 K to 573 K are successfully detected by using the LAST method. Show more

Keywords: Laser array spots thermography, surface cracks, elevated temperature, non-destructive testing

DOI: 10.3233/JAE-171195

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1553-1559, 2019

Authors: Jun, Tu | Gongzhe, Qiu | Xiaochun, Song | Xu, Zhang | Donglin, Li

Article Type: Research Article

Abstract: The circular array sensor arrangement and time reversal technique are applied in the present ultrasonic imaging method, of which the testing efficiency and flexibility is limited for the large scale steel plate. In this paper, a Lamb wave imaging method based on the linear array focusing-time reversal (LAFTR) technique is presented. The steps of the LAFTR imaging method for large scale steel plate are concluded. The COMSOL software is used to establish the finite element model for the steel plate testing based on LAFTR method, and the MATLAB software is used to realize the imaging program. Finally the experimental results …indicate that the LAFTR method can get high precision images for the steel plate. Show more

Keywords: Linear array focusing, time reversal, steel plate testing, ultrasonic imaging

DOI: 10.3233/JAE-171173

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1561-1569, 2019