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

Authors: Xu, Jiang | Wu, Xinjun | Kang, Yihua

Article Type: Research Article

Abstract: The guided wave technology is usually applied to detect defects in the regular zone. In this paper, the guided wave technology is applied to detect the flaw in the transition zone of sucker rods where is an irregular zone. A piecewise model is established by making a difference between the down step flaw and the up step flaw. The experiments are carried on a sucker rod sample with the artificial notch flaws in the transition zone using …magnetostrictive guided waves. The experimental results agree well with the theoretical predictions. The result indicates that the guided wave technology could be applied to inspect some special irregular structures. Show more

Keywords: Transition zone, sucker rod, guided waves, magnetostritive effect, nondestructive testing

DOI: 10.3233/JAE-2012-1465

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 229-235, 2012

Authors: Kurihara, Kenji | Naitou, Keiichi | Sugiura, Toshihiko

Article Type: Research Article

Abstract: Detection and sizing of a closed crack in structures are difficult by conventional ultrasonic testing. One of promising alternative methods is nonlinear ultrasonic testing which detects subharmonic responses from a closed crack. This study investigates generation of subharmonics at contact surfaces of two specimens, modeling a closed crack, under ultrasonic radiation. Experiments of ultrasonic inspection were carried out by preparing different kinds of surface roughness of the specimens and also by changing compression …force acting on the two contacting specimens. Our experimental results show some subharmonic responses from the contact surfaces, which can be influenced by the contact pressure and the contact surface roughness. Show more

Keywords: Nondestructive testing, nonlinear ultrasonic, subharmonics

DOI: 10.3233/JAE-2012-1466

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 237-243, 2012

Authors: Zorni, Chiara | Reboud, Christophe | Decitre, Jean-Marc | Santandréa, Laurent | Bihan, Yann Le | Ventre, Salvatore | Tamburrino, Antonello | Lambert, Marc

Article Type: Research Article

Abstract: Three numerical approaches ((i) a semi-analytical model based on a volume integral method; (ii) an integral formulation solved in terms of a finite-element approximation; (iii) a finite-element solver using complementary magnetic and electrical formulations) modelling the response of a probe to the presence of a defect affecting a planar-stratified ferromagnetic material are presented and their results compared with one another and with experimental or numerical results of literature.

Keywords: Integral formulation, dyadic Green functions, finite element method, ferromagnetism, cracks, eddy current testing

DOI: 10.3233/JAE-2012-1467

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 245-250, 2012

Authors: Cheng, Jun | Qiu, Jinhao | Takagi, Toshiyuki | Uchimoto, Tetsuya | Hu, Ning

Article Type: Research Article

Abstract: This paper deals with eddy current testing simulation for carbon-fibre reinforced polymer composites (CFRPs) using an edge – element FEM code. The FEM code is based on the A formulation and it uses the coupled analysis with external fields. The coil impedance variations due to the fibre orientation and cracks in CFRP plates with unidirectional plies are computed. The conductivity of CFRP is characterized as low value and high anisotropy, which cause the distinct difference between …CFRP and isotropic metal ECT signals. The correlation of the fibre orientation with coil impedance variations is obtained, but the exact fibre arrangement in a composite plate can't be ascertained because of signal symmetry. Another method for determining the fibre orientation via the edge effect is presented in this study. According to the numerical results, the shape of cracks in a CFRP plate is not easily evaluated from the detection signal curves unless the fibre orientation is perpendicular to the crack path. Show more

Keywords: Carbon-fibre reinforced polymer, Eddy Current Testing, numerical simulation, Finite Element Method, fibre orientation

DOI: 10.3233/JAE-2012-1468

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 251-259, 2012

Authors: Uchimoto, Tetsuya | Takagi, Toshiyuki | Ohtaki, Keitaro | Takeda, Yoichi | Kawakami, Akira

Article Type: Research Article

Abstract: This study discusses the electromagnetic modeling of fatigue cracks in plant environment to improve accuracy of depth sizing with eddy current testing. For the purpose, the factors that influence eddy current signals of fatigue cracks are evaluated. Here, martensitic layer and oxide fillings in fatigue cracks are focused on as influencing factors, and oxides are systematically filled in fatigue cracks by thermal treatment. The measured EC signals change depending on the presence and type of filling …oxides. Numerical simulations are conducted to discuss the electromagnetic modeling of cracks with oxide fillings. The types of oxides in the cracks are identified by Raman spectroscopy, and the martensitic layers in vicinity of crack faces are observed by magnetic force microscopy. These results support for the electromagnetic model of environmental fatigue cracks developed in this study. Show more

Keywords: Eddy current testing, environmental fatigue, depth sizing, oxidation, martensitic phase

DOI: 10.3233/JAE-2012-1469

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 261-268, 2012

Authors: Tian, Gui Yun | He, Yunze | Cheng, Liang | Jackson, Paul

Article Type: Research Article

Abstract: Corrosion characterisation on metal substrates is a major problem in the field of corrosion science and Non-destructive Evaluation (NDE). In this work, the electromagnetic NDE method, Pulsed Eddy Current (PEC) Thermography, has been applied to evaluate the corrosion on the mild steel plates. By analysis of heat induction and heat diffusion, early stage thermal images are proposed to avoid the lateral heat diffusion and to detect the corrosion progression more accurately. Principal Component Analysis (PCA) is …used to extract the variation information from the different time period image sequences to improve the imaging quality and to validate the early detection theory. Results show that PEC thermography has potential as a rapid tool for corrosion characterisation. Show more

Keywords: Corrosion, pulsed eddy current thermography, heat diffusion, early detection, principal component analysis

DOI: 10.3233/JAE-2012-1470

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 269-276, 2012

Authors: Smetana, Milan | Janousek, Ladislav

Article Type: Research Article

Abstract: The article deals with utilization of two various types of sensing elements in eddy current non-destructive testing. An inductance coil and a fluxgate magnetometer are employed to pick-up the response signals from artificial slits. The sensitivity and the resolution of the two types of sensors are analysed under the same conditions. The sensors' performances are compared under the harmonic excitation and the pulsed one as well. Numerical simulations and experimental measurements are carried out for performing …the evaluation. The gained results are presented and discussed in the paper. Show more

Keywords: Non-destructive inspection, eddy currents, harmonic and pulsed excitations, inductance coil, fluxgate magnetometer, excitation and sensing system

DOI: 10.3233/JAE-2012-1471

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 277-282, 2012

Authors: Cherry, Matthew | Knopp, Jeremy | Blodgett, Mark | Grandhi, Ramana

Article Type: Research Article

Abstract: Eddy current detection of flaws in edges presents challenges in experimental procedures during benchmark studies in the laboratory for model validation as well as practical implementation of a real world detection system. These difficulties result in distortions to the signal that mask the effects from the flawed region itself. Rather than attempting to perfect the experimental setup, we propose to make the numerical models more robust by incorporating randomness in the experimental procedure with uncertainty …quantification methods. We present the motivation for the specific method chosen, the probabilistic collocation method (PCM), and the mathematical development behind the method, and then present the results from numerical simulations with a validation measure. Show more

Keywords: Probabilistic, collocation, eddy, current

DOI: 10.3233/JAE-2012-1472

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 283-289, 2012

Authors: Yusa, Noritaka | Hashizume, Hidetoshi

Article Type: Research Article

Abstract: This study proposes a method to fabricate artificial flaws whose response to non-destructive testing, especially electromagnetic non-destructive testing, is the same as that of stress corrosion cracking. Stacked metallic films containing through-grooves are sandwiched between metallic blocks and then bonded using solid state bonding. The profiles of the through-grooves are accurately controlled with the aid of the lithography technique, which allows a three-dimensional discontinuity to be embedded inside a material. Since the …spatial distribution of the discontinuity is small compared to the spatial resolution of non-destructive testing methods, the method allows the response of stress corrosion cracking to be simulated. Specimens are fabricated using type 316 L austenitic stainless steel, and validated using eddy current testing. Show more

Keywords: Non-destructive testing and evaluation, electromagnetic non-destructive testing, finite element simulations, electric resistance, modelling

DOI: 10.3233/JAE-2012-1473

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 291-296, 2012

Authors: Garcia-Rodriguez, Daniel | Mihalache, Ovidiu | Ueda, Masashi

Article Type: Research Article

Abstract: Two-dimensional axis-symmetric finite element method (FEM) simulations are conducted to study remote field eddy current testing (RF-ECT) in ferromagnetic steam generator (SG) tubes for fast breeder reactors (FBR). The present work investigates a combination of quasi-static and transient analysis with both linear and non-linear material properties. Two FEM codes are employed: a commercial one based on COMSOL and a 2D-FEM code developed in-house. Both codes are used to evaluate the influence of the speed of the …ECT probe during in-service inspection of SG tubes at a low excitation frequency. As a result, the maximum error in SG tube defect detection when using the classical linear and quasi-static approximations is obtained. Show more

Keywords: Steam generator, fast breeder reactor, remote-field eddy current, non-linear, ferromagnetic, time transient, speed effect, finite element

DOI: 10.3233/JAE-2012-1474

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 297-303, 2012