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