International Journal of Applied Electromagnetics and Mechanics - Volume 39, issue 1-4

Authors: Kinoshita, Katsuyuki | Hasegawa, Yu | Matsumoto, Eiji

Article Type: Research Article

Abstract: We report a novel non-destructive evaluation method (NDE) that relies on the magnetic properties of the inherent ferromagnetic phase in austenitic stainless steel (SUS) parts to assess the state of damage. The effects of the volume fraction, internal stress, and shape anisotropy of the ferromagnetic phase on the electromagnetic impedance signal used in the NDE are discussed on the basis of experimental results for cold-rolled SUS 304 steel plates of different thicknesses with and without stress …relief annealing. In particular, the influence of shape anisotropy is clarified on the basis of measurements conducted on 0.5-mm-thick samples both parallel and perpendicular to the rolling direction. The results of the measurements show that the parameters obtained by the proposed method are indicative of damage. Show more

Keywords: Austenitic stainless steel, non-destructive evaluation method, work-affected layer

DOI: 10.3233/JAE-2012-1485

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 375-380, 2012

Authors: Tsuchida, Yuji | Kai, Yuichiro | Enokizono, Masato

Article Type: Research Article

Abstract: In the conventional eddy current testing (ECT), it is difficult to estimate wall thinning from outside of pipes without removing the covered materials due to the large lift-off between a pipe surface and a sensor. In order to overcome this difficulty, a long-pulsed excitation system has been developed with a magnetic sensor, by which the magnetic flux can be penetrated deeply inside pipes because of low frequency and small induced eddy current. In this paper, the …numerical results and measured results of the newly developed long-pulsed excitation system are shown. The results show the effectiveness of the proposed long-pulsed method for a large lift-off evaluation to wall thinning. Show more

Keywords: Long-pulsed excitation, magnetic sensor, pipe wall thinning, large lift-off, low frequency excitation

DOI: 10.3233/JAE-2012-1486

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 381-388, 2012

Authors: Yang, Guang | Khan, Tariq | Zhang, Lu | Dib, Gerges | Xin, Junjun | Udpa, Lalita | Majumdar, Shantanu | Udpa, Satish | Kim, Jaejoon

Article Type: Research Article

Abstract: An advanced nonlinear, non-stationary signal processing algorithm using Hilbert-Huang Transform is presented for automatic analysis of eddy current data collected during the inspection of steam generator tubes in nuclear power plants. The proposed algorithm reduces noise and enhances defect indication in the signal, thereby yielding increased detection probability as well as reduced false calls. Results of applying the algorithm on field data from SG tube inspection are presented and compared with those of current …practice in industry. Show more

Keywords: Eddy current steam generator tube inspection, fourier domain median filter, Hilbert-Huang Transform (HHT), ROI detection

DOI: 10.3233/JAE-2012-1487

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 389-395, 2012

Authors: Skarlatos, Anastassios | Reboud, Christophe | Decitre, Jean-Marc | Mahaut, Steve

Article Type: Research Article

Abstract: The volume integral method is combined with a circuit solver for the modelling of eddy-current inspection applications by taking into account the effect of the measuring circuit. It is demonstrated that the latter may result in noticeable deformations of the acquisition signals for specific inspection situations, thus it cannot be eliminated by simple calibration; this effect becomes increasingly important when the measuring frequency approaches the probe resonance. Comparisons of the simulation results with experimental data …demonstrate the necessity of accounting for the circuit effect for inspection in driver pickup mode and verify the validity of the approach. Show more

Keywords: Eddy-current testing modelling, circuit effect, volume integral method, coupled electromagnetic/circuit modelling

DOI: 10.3233/JAE-2012-1488

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 397-403, 2012

Authors: Pei, Cuixiang | Demachi, Kazuyuki | Zhu, Haitao | Koyama, Kazuyoshi | Uesaka, Mitsuru

Article Type: Research Article

Abstract: In this paper, a numerical code is developed for the analysis of phased-array laser ultrasound. The signal enhancement of ultrasonic waves induced by a multi-beam laser source in phased array is simulated by using finite element method (FEM). The use of phased-array laser ultrasound for crack inspection with shadow method is investigated by simulation method.

Keywords: Laser ultrasonic, phased-array method, nondestructive testing, numerical simulation

DOI: 10.3233/JAE-2012-1489

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 405-411, 2012

Authors: Nishimura, Yoshihiro | Suzuki, Takayuki | Kondo, Naoki | Kita, Hideki | Hirao, Kiyoshi

Article Type: Research Article

Abstract: The possibility of inspecting flaws in ceramic materials using Ultrasonic Testing (UT) and X-Ray methods was studied to investigate the reliability of ceramic material joints. First, Scanning Electron Microscope (SEM) images of two grades of ceramics were compared to those acquired by a scanning acoustic microscope (SAM) with respect to the number, and size of flaws. Second, ceramic sample with a known size of internal voids was evaluated by X-Ray-CT. Third, two jointed ceramic specimens were …evaluated by X-Ray methods, SAM, and other UT methods. X-Ray methods and UT methods effectively established the safety of ceramic materials for structural uses. Show more

Keywords: Silicon nitride, flaws, ultrasound, X-Ray/CT

DOI: 10.3233/JAE-2012-1490

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 413-418, 2012

Authors: Takahashi, Yohei | Urayama, Ryoichi | Uchimoto, Tetsuya | Takagi, Toshiyuki | Naganuma, Hiroshi | Sugawara, Kazufumi | Sasaki, Yoriaki

Article Type: Research Article

Abstract: This paper discusses the feasibility of thickness evaluation of Ni-based alloy coating sprayed on type 304 austenitic stainless steels by swept frequency eddy current testing which measures the impedance spectra of coil. Comparing the experimental signals with the numerical ones, the electromagnetic models of coating are developed. Using these models, the inverse analyses are conducted. The coating thicknesses are estimated within the maximum error of 22 μm.

Keywords: Thermal spraying, coating thickness, swept frequency eddy current testing, inverse analysis

DOI: 10.3233/JAE-2012-1491

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 419-425, 2012

Authors: Lopato, Przemyslaw | Chady, Tomasz

Article Type: Research Article

Abstract: Nondestructive testing using terahertz frequency electromagnetic waves is becoming increasingly popular method of inspection. Similar operating principle allows the use of inverse algorithms derived from the ultrasonic technique. In this paper algorithm and results of time reversal processing applied to pulsed terahertz inspection of dielectric objects are presented. Time reversal is implemented using finite difference time domain method. New criteria of optimal focusing time are proposed in order to estimate defects positions. …Finally the algorithm is verified using the results of simulations and measurements. Show more

Keywords: THz waves time domain measurements, time reversal processing, THz wave propagation numerical modelling

DOI: 10.3233/JAE-2012-1492

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 427-433, 2012

Authors: Smail, M.K. | Le Bihan, Y. | Pichon, L.

Article Type: Research Article

Abstract: A fast diagnosis dedicated to embedded transmission lines and based on time domain reflectometry is presented. The forward problem allows to simulate the propagation along the wiring network as well as to create datasets for the inverse problem resolution. Neural networks (NNs) are used to solve the inverse problem which consists to find defects on the wire from the reflectometry response. The significant parameters of the reflectometry response data are extracted using principal component analysis. This …method allows an efficient reduction of the dimension of the reflectometry data space. Show more

Keywords: Wiring network, multiconductor transmission lines, FDTD method, time domain reflectometry, reconstruction, neural network and principal component analysis

DOI: 10.3233/JAE-2012-1493

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 435-441, 2012

Authors: Zhao, Yanzhen | Ma, Xikui | Yang, Jichao

Article Type: Research Article

Abstract: Inter-turn short circuit faults are among the common faults occurring in dry-type air-core reactor. This paper presents an online detection method of inter-turn short circuit faults for dry-type air-core reactors by using search coils. Since this type of fault creates shorted turns in which there are high induced currents that can produce intense reversed magnetic field, the magnetic field distribution is no longer symmetrical. The variety of magnetic field from the normal condition to the fault …condition can be monitored by search coils. Based on coupled field circuit method, the magnetic field distribution of the reactor and the induction voltage of the search coils are computed in different conditions. The proper mounted positions of search coils are suggested. The proposed method has been verified to be effective and easy for implementation by experimentation. Show more

Keywords: Dry-type air-core reactor, inter-turn short circuit faults, faults detection, search coil, coupled field circuit method

DOI: 10.3233/JAE-2012-1494

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 443-449, 2012