International Journal of Applied Electromagnetics and Mechanics - Volume 64, issue 1-4

Authors: Qiu, Jinhao | Xiong, Ke | Ji, Hongli

Article Type: Editorial

DOI: 10.3233/JAE-209300

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 1-1, 2020

Authors: Wang, Lihui | Zhao, Kai | Zhang, Wenpeng | Liu, Jian | Pang, Fubin

Article Type: Research Article

Abstract: Affected by environmental factors, the performance of fiber optic current transformer (FOCT) will deteriorate over a long period of time. Intelligent fault diagnosis algorithm of Long-Short Term Memory (LSTM) combing with Support Vector Machine (SVM) is an effective way to deal with FOCT failures. According to the characteristics of LSTM, a signal prediction model in FOCT based on LSTM is proposed by analyzing the historical data. The residual signal can be obtained by the prediction signal and the observed signal. Set the residual threshold to determine whether the FOCT has fault. With the residual signal characteristics, a fault diagnosis model …based on SVM is established. By analyzing the residual signal and extracting features, the diagnostic network can realize the pattern recognition and system fault diagnosis. Experiments demonstrate that the drift deviation fault, the ratio deviation fault and the fixed deviation fault can be diagnosed with an accuracy of 94.5%. Show more

Keywords: Fiber optic current transformer, fault feature, fault diagnosis, long-short term memory

DOI: 10.3233/JAE-209301

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 3-10, 2020

Authors: Yusa, Noritaka | Tomizawa, Takuma | Song, Haicheng

Article Type: Research Article

Abstract: This study proposes a method to probabilistically evaluate the area of coverage of nondestructive inspections to detect defects on a surface of a structure. For the specific problem, this study considers the effect of the distance between two neighboring scanning lines on the detectability of eddy current testing against near-side cracks. Thirty-eight type 316L stainless steel plates having a fatigue crack were prepared, and eddy current examinations were performed with a sufficiently fine scanning pitch. The full width at half maximum of the spatial distribution of the amplitude of the signals was approximated using a Gaussian function. A probability of …detection model considering the distance between two neighboring scanning lines is proposed because in actual inspections a scanning line does not always run directly above a crack. The results demonstrated that the proposed model enables a reasonable probabilistic evaluation of the effect of the distance between two neighboring scanning lines. Show more

Keywords: Electromagnetic nondestructive evaluation, probability of detection, surface breaking crack, fatigue crack, austenitic stainless steel, coverage path, Monte Carlo simulation, uncertainty

DOI: 10.3233/JAE-209302

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 11-18, 2020

Authors: Ren, Shuting | Li, Yong | Yan, Bei | Hu, Jinhua | Zainal Abidin, Ilham Mukriz | Chen, Hongen

Article Type: Research Article

Abstract: Structures of nonmagnetic materials are broadly used in engineering fields such as aerospace, energy, etc. Due to corrosive and hostile environments, they are vulnerable to the Subsurface Pitting Corrosion (SPC) leading to structural failure. Therefore, it is imperative to conduct periodical inspection and comprehensive evaluation of SPC using reliable nondestructive evaluation techniques. Extended from the conventional Pulsed eddy current method (PEC), Gradient-field Pulsed Eddy Current technique (GPEC) has been proposed and found to be advantageous over PEC in terms of enhanced inspection sensitivity and accuracy in evaluation and imaging of subsurface defects in nonmagnetic conductors. In this paper two GPEC …probes for uniform field excitation are intensively analyzed and compared. Their capabilities in SPC evaluation and imaging are explored through simulations and experiments. The optimal position for deployment of the magnetic field sensor is determined by scrutinizing the field uniformity and inspection sensitivity to SPC based on finite element simulations. After the optimal probe structure is chosen, quantitative evaluation and imaging of SPC are investigated. Signal/image processing algorithms for SPC evaluation are proposed. Through simulations and experiments, it has been found that the T-shaped probe together with the proposed processing algorithms is advantageous and preferable for profile recognition and depth evaluation of SPC. Show more

Keywords: Electromagnetic nondestructive evaluation, gradient-field pulsed eddy current inspection, subsurface pitting corrosion, corrosion imaging, signal/image processing

DOI: 10.3233/JAE-209303

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 19-29, 2020

Authors: Monkrathok, Jirawan | Srithorn, Jongkol | Phung-On, Isaratat | Phatthanakun, Rungrueang

Article Type: Research Article

Abstract: In this research, the Synchrotron X-ray lithography (X-ray LIGA) was implemented to fabricate imitative Stress Corrosion Crack (SCC) for using as a reference specimen of electromagnetic NDT. A pattern of the imitative SCC was created by using X-ray LIGA with controllable shape and size in precise details. The pattern created had a high aspect ratio, which was formed on SU-8 polymer. As a preliminary experiment, the prepared pattern was inserted into a block of pure Nickel formed by an electroplating technique. To develop a reference comparable to stainless steel in terms of electromagnetic response, the technique called “Suspension Electroplating” was …implemented to create a block of material from its powder form. A rough magnetic response was then measured by Eddy Current Testing (ECT). The results showed the possibility of creating the desired properties of stainless steel. The SCC pattern will be then inserted to become the reference specimen. Show more

Keywords: Imitative crack, lithography, electroplating, eddy current testing

DOI: 10.3233/JAE-209304

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 31-37, 2020

Authors: Chen, Guanren | Katagiri, Takuya | Yusa, Noritaka | Hashizume, Hidetoshi

Article Type: Research Article

Abstract: This study evaluated the effect of pipe diameter on the applicability of a technique using TE11 mode microwaves for in-pipe crack detection. Three TE11 mode converters of different inner diameters were designed based on theoretical calculations and verified via numerical simulations. The working bandwidths of these mode converters were 7.0, 4.0, and 1.9 GHz. Experimental verification was carried out using brass pipes with the corresponding three inner diameters, and with pipe lengths up to 21–25.5 m. An axial and a circumferential slit were introduced to simulate cracks and deployed at multiple positions along the pipes under test. The results showed …that both axial and circumferential slits could be detected and located for an inner pipe diameter up to 39 mm and at a distance of 15 m–24 m. Show more

Keywords: Microwaves, TE11, NDT, mode converter, crack

DOI: 10.3233/JAE-209305

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 39-46, 2020

Authors: Tomizawa, Takuma | Song, Haicheng | Yusa, Noritaka

Article Type: Research Article

Abstract: This study proposes a probability of detection (POD) model to quantitatively evaluate the capability of eddy current testing to detect flaws on the inner surface of pressure vessels cladded by stainless steel and in the presence of high noise level. Welded plate samples with drill holes were prepared to simulate corrosion that typically appears on the inner surface of large-scale pressure vessels. The signals generated by the drill holes and the noise caused by the weld were examined using eddy current testing. A hit/miss-based POD model with multiple flaw parameters and multiple signal features was proposed to analyze the measured …signals. It is shown that the proposed model is able to more reasonably characterize the detectability of eddy current signals compared to conventional models that consider a single signal feature. Show more

Keywords: POD, multi-parameter, weld, corrosion, pressure vessel

DOI: 10.3233/JAE-209306

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 47-55, 2020

Authors: Okobira, Tatsuya | Nguyen, Dang-Trang | Taguchi, Kozo

Article Type: Research Article

Abstract: Many efforts have been devoted to the improvement of metal-air batteries. Aluminum (Al) is the most abundant metal in the Earth’s crust and has high electrochemical potential. Therefore, the aluminum-air battery is one of the most attractive metal-air batteries. To overcome some disadvantages of the aluminum-air battery, some alloys of aluminum and several metals have been proposed. In this study, the performance improvement of the aluminum-air battery by doping zinc (Zn) to the aluminum anode was investigated. Zinc was doped to aluminum by a simple process. The difference in the characteristics of Zn-doped Al due to different heating temperature during …the doping process was also investigated. The maximum power density of the battery was 2.5 mW/cm2 . Show more

Keywords: Aluminum-air battery, dope, zinc, simple method, ozone treatment

DOI: 10.3233/JAE-209307

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 57-64, 2020

Authors: Tsuji, Yuhei | Nguyen, Dang-Trang | Taguchi, Kozo

Article Type: Research Article

Abstract: This study focused on investigating low-cost but high-performance catalyst materials used for the air cathode of the aluminum-air battery. Nickel, in the form of Ni(OH)2 , was used as the catalyst because it is abundant and low-cost. The activated carbon sheet was used as the substrate to load the catalyst. The solvothermal synthesis method was used to synthesize the catalyst. The advantage of the solvothermal method is that the particle size can be reduced under high temperature and pressure conditions. The operation of some types of air-cathodes was examined. UV-ozone treatment of the air-cathode has also been investigated to enhance …the performance of the battery. Show more

Keywords: Air cathode, Nickel hydroxide, metal-air battery, UV-ozone cleaning

DOI: 10.3233/JAE-209308

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 65-71, 2020

Authors: Cluet, Raphaël | Maïzi, Nadia | Mazauric, Vincent

Article Type: Research Article

Abstract: This paper reviews the conditions for ensuring the space consolidation and time reconciliation of all scales involved in power system energy planning. At the upper space scale, a simplified description of the grid based on the Kuramoto model is adopted to assess the stability of the synchronism state of the power system. The consequences of a massive dissemination of renewables for the future of the power system is addressed in the case of France in a long-term planning exercise up to 2050. Attention is paid to how the new capacities are dispatched among the administrative regions. While a favorable impact …of sparse generation on the synchronism is obtained, the constraint on the inertia provided by the kinetic energy has to be endogenized to enforce an operable power mix under admissible disturbances. Show more

Keywords: Power generation, energy planning, transient stability, space aggregation, France

DOI: 10.3233/JAE-209309

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 73-78, 2020