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

Authors: Zhang, Jianxun | Qin, Qinghua | Yang, Yan | Yu, Xuehui | Xie, Shejuan | Wang, T.J.

Article Type: Research Article

Abstract: The objective of this work is to investigate dynamic response of fully clamped slender foam-filled rectangular tubes subjected to low-velocity impact. Analytical and numerical analysis are presented to predict the dynamic response of the fully clamped slender foam-filled rectangular tubes struck by a low-velocity heavy mass. In the analytical solutions, the interaction of bending and stretching induced by large deflections is considered. Good agreement is achieved between the analytical solutions and numerical results. It is shown that the filled foam strength has significant effect on the impact resistance capacity of foam-filled tubes.

Keywords: Foam-filled rectangular tube, low-velocity impact, overall bending

DOI: 10.3233/JAE-171080

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1441-1449, 2019

Authors: Kojima, Fumio

Article Type: Research Article

Abstract: This study is concerned with the identification of internal temperature distribution of metal products using pulser-receiver EMAT. The problem treated here is converted into the characterization of elastic properties using ultrasonic data obtained from EMAT devices. Then the internal temperature can be estimated from the inverse mapping of temperature-to-elastic dependency. First, the mechanisms of pulser-receiver EMAT are derived from Maxwell equations. Secondly, the dynamics of ultrasonic wave propagation is given by an elastic equation with unknown parameters. A computational method for identifying elastic parameters is proposed. The applicability and validity of the proposed method are shown using syntheses data.

Keywords: Inversion, ultrasonic testing, signal processing, in-line measurement, continuous casting

DOI: 10.3233/JAE-171013

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1451-1457, 2019

Authors: Li, Yong | Wang, Yi | Yan, Bei | Cai, Rui | Chen, Zhenmao | Abidin, Ilham Mukriz Zainal | Jing, Haoqing

Article Type: Research Article

Abstract: In-service tubular conductors are prone to such anomalies as the wall-thinning defect and hidden corrosion which pose a severe threat to structural integrity. In this paper, a capsule-typed electromagnetic acoustic transducer is proposed for inspection of tubular conductors such as small-diameter pipes subject to external corrosion. An efficient hybrid model of Electromagnetic Acoustic Transduction (EMAT) is established in an effort to reveal the underlying physical phenomena and simulate the resulting responses to external wall-thinning defects in tubular conductors. The model integrates a fast analytical model computing the electromagnetic field and resulting Lorentz force with Finite Element Modeling (FEM) for simulation …of ultrasonic field. The established model is corroborated via FEM and experiments, and beneficial to the optimization of the proposed capsule-typed electromagnetic acoustic transducer for non-destructive evaluation of tubular conductors. Show more

Keywords: Electromagnetic non-destructive evaluation, electromagnetic acoustic transduction, tubular conductor, analytical modeling, hybrid model

DOI: 10.3233/JAE-171006

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1459-1467, 2019

Authors: Yamaguchi, Toshihiko | Mihalache, Ovidiu | Ueda, Masashi

Article Type: Research Article

Abstract: The paper presents the progress in the developments of an electro-magnetic acoustic transducer (EMAT) based on a Halbach magnet system optimized for detection of defects in thick plates with application to the inspection of fast breeder reactors (FBR) vessel. The defects are located either far or near weld lines in austenitic stainless steel plates (50 mm thick), on the opposite plate side where are located the EMAT sensors. Performance of single or double units EMATs are investigated for working in industrial conditions with very long cables (up to 45 m). Experimental measurements are focused on an increased signal/noise ratio for …detection of signal from defects located near weld lines of FBR vessel. A fast and novel way of EMAT measurements and signal processing (named dynamic scanning) is introduced and its performance is confirmed for austenitic stainless steel plate defects with depths ranging from 5% to 50% from the plate thickness. Show more

Keywords: Fast breeder reactor vessel, austenitic steel, EMAT, welds, C-scan

DOI: 10.3233/JAE-171226

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1469-1477, 2019

Authors: Wang, Zhe | Cui, Ximing | Pu, Haiming | Kang, Yihua

Article Type: Research Article

Abstract: In order to illustrate influence of surface roughness on the energy change of excitation process in thickness measurement of electromagnetic acoustic transducer (EMAT), the change of Lorentz force during the excitation process is analyzed theoretically. A finite element simulation model of EMAT is established with different surface roughness. The distribution of eddy current density and Lorentz force density of different rough surface is discussed. The results show that the eddy current density gets nonuniform due to the irregular profile of the surface. The average value of Lorentz force density decreases with the increase of surface roughness Ra, which makes the …excitation energy of EMAT get weaker. Finally, the experiment results verify the analysis of the theory and finite element simulation. Show more

Keywords: Surface roughness, eddy current density, Lorentz force density, excitation energy change, EMAT

DOI: 10.3233/JAE-171121

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1479-1486, 2019

Authors: Nakamoto, Hiroyuki | Nakamura, Daichi | Kojima, Fumio | Komatsu, Keiichi | Tomita, Hideaki

Article Type: Research Article

Abstract: Maintenance of aging infrastructure facilities in urban area is a critical issue. Actually, in Kobe city, two illumination pillars fell down because they had corrosion under the ground line. This study aims to detect corrosion of illumination pillars using ultrasonic guided wave generated by electromagnetic acoustic transducer (EMAT). The guided wave is expected as a quick and long distance inspection technology for piping systems. In this study, a guided wave inspection system using the EMATs is proposed. The guided wave inspection system detects corrosion by reflected waves from corrosion. The effectiveness of the proposed system for screening of corrosion in …illumination pillars is verified through experiments using both retired and active illumination pillars. Show more

Keywords: Nondestructive evaluation, electromagnetic acoustic transducer, guided wave

DOI: 10.3233/JAE-171113

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1487-1493, 2019

Authors: Sun, Hongjun | Urayama, Ryoichi | Hashimoto, Mitsuo | Kojima, Fumio | Uchimoto, Tetsuya | Takagi, Toshiyuki

Article Type: Research Article

Abstract: Intense ultrasonic waves are required to accurately measure the thickness of corroded specimen at a given point. The most intense part of the ultrasonic wave should be at the measurement point itself. In this paper, finite element simulation is used to optimize the structure of the classic racetrack coil bulk wave electromagnetic acoustic transducer to produce more intense, concentrated ultrasonic waves in a smaller area. In addition, a new magnet configuration is used that increases the wave intensity. Compared with the classic magnet configuration, the maximum amplitude of the ultrasonic wave is increased by 21%.

Keywords: Electromagnetic acoustic transducer, racetrack coil, magnet configuration

DOI: 10.3233/JAE-171106

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1495-1504, 2019

Authors: Park, Won-Kwang

Article Type: Research Article

Abstract: We investigate a fast algorithm to search for the location of a small anomaly by using microwave. The algorithm is based on the structure of nonzero singular vectors associated with nonzero singular values of a complex-symmetric matrix, whose elements are measured S -parameters. Experimental and simulated results show the effectiveness and limitations of the investigated algorithm for real-world microwave imaging.

Keywords: Fast algorithm, microwave, S-parameters, experimental results

DOI: 10.3233/JAE-171107

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1505-1510, 2019

Authors: Chady, Tomasz | Gorący, Krzysztof

Article Type: Research Article

Abstract: There are many nondestructive methods of coatings evaluation. Only a few of them can be utilized in case of coatings deposited on nonconductive elements. This paper presents application of a terahertz time domain spectroscopy for measuring thickness of thin nonconductive coatings. In order to develop a robust algorithm for thickness identification various experiments were carried out. A metal vessel filled with a small amount of oil was used as the test specimen. Such specimen allows us to easily achieve sample with a variable coating thickness.

Keywords: Non-destructive testing, coatings, terahertz

DOI: 10.3233/JAE-171063

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1511-1517, 2019

Authors: Uoshita, Shoya | Sasaki, Kota | Katagiri, Takuya | Yusa, Noritaka | Hashizume, Hidetoshi

Article Type: Research Article

Abstract: This study evaluated the effect of bends on the long-range nondestructive testing inspection of pipe surfaces based on microwaves propagating inside the pipe. Three-dimensional finite element simulations were conducted to reveal electromagnetic fields at bends with a diameter of 23 mm and various radii of curvature when microwaves were emitted into a pipe in the TM01 mode that had been mainly used in earlier studies. The simulations revealed that the effect of the bend on the microwaves is not significant when the ratio of curvature is larger than approximately 2, whereas in general a bend reflects a part of microwaves …and causes non-TM01 modes. Subsequent experimental verifications, which used a pipe with a total length of approximately 4 m and a 90-degree or 180-degree bend, confirmed clear reflections due to artificial wall thinning in spite of the presence of the bend. Show more

Keywords: Electromagnetic nondestructive evaluation, wall thinning, pipe degradation, time of flight, electromagnetic wave, finite element simulation

DOI: 10.3233/JAE-171001

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1519-1526, 2019

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