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

Authors: Areiza, Maria C.L. | Sacramento, Rodrigo | Rebello, Joao M.A | Sommer, Rubem L. | Gonzalez, Diego

Article Type: Research Article

Abstract: Avoiding accidents caused by equipment failure and ensuring structure quality are some of the challenges of the petroleum industry. Petroleum exploitation in salt-water has required the use of special materials, such as duplex stainless steels (DSS), that support highly aggressive corrosion conditions and, at the same time, are ductile facilitating equipment manufacture. But DSS can be embrittled when exposed to some heat treatments, such as welding (T > 800 deg). Deleterious phases might …precipitated in this material, especially sigma phase (σ), which appears in higher volumetric fraction. This paper presents a proposal of a characterization procedure of deleterious phases in DSS using Eddy Current Technique (EC). A calculus model was elaborated using finite elements. The model was able to reproduce the behavior of this type of steel, and it will help to correctly recognize the signals generated by the material's internal defects. Show more

Keywords: Duplex, characterization using eddy current, detecting deleterious phase in duplex

DOI: 10.3233/JAE-2012-1475

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 305-310, 2012

Authors: Fukuoka, Katsuhiro | Hashimoto, Mitsuo

Article Type: Research Article

Abstract: We designed exciting coils of uniform eddy current multiprobes with considering the shape of structures in order to obtain a uniform eddy current flow. A probe for a flat plate could obtain clear signals for an electrical discharge machining (EDM) slit of depth 0.5 mm and distinguish EDM slits arranged at 2 mm intervals. We confirmed that stress corrosion cracking (SCC) is detectable with sufficient sensitivity using the developed multiprobe. The probe for a curved portion …obtained clear signals for the EDM slits on a curved surface of radius 25 mm. Moreover, we examined the technique for estimating crack shape from detection signals. Show more

Keywords: Eddy current testing (ECT), uniform eddy current probe, multiprobe, stress corrosion cracking (SCC), curved portion, estimation of crack shape

DOI: 10.3233/JAE-2012-1476

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 311-317, 2012

Authors: Matsuda, Taisuke | Tsuchida, Yuji | Enokizono, Masato

Article Type: Research Article

Abstract: This paper presents a frequency sweeping excitation and spectrogram method (FSES method) by magnetic sensor for non-destructive testing of hardened carbon steel. High frequency induction heating can make changes in the microstructure and residual stress. As a result, the magnetic properties such as magnetic permeability, magnetic coercivity and remanent magnetization in materials are changed. This makes it possible to evaluate the hardening conditions by using the FSES method. We tried to examine the degree of yield …strength which varies with hardened conditions. Controlling and evaluating of yield strength are very important for actual industrial products. Show more

Keywords: Non-destructive testing, hardened carbon steel, magnetic property, magnetic sensor, yield strength

DOI: 10.3233/JAE-2012-1477

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 319-327, 2012

Authors: Janousek, Ladislav | Smetana, Milan | Alman, Marcel

Article Type: Research Article

Abstract: The paper deals with eddy current non-destructive inspection of partially conductive cracks. A non-magnetic conductive plate specimen is examined using numerical simulations. A crack with the rectangular shape is modelled in the middle of plate. Dimensional parameters and the conductivity of the crack are varied in wide ranges to imitate diversity of practical scenarios. A new eddy current probe is designed for the near-side inspection of the plate. An exciting system of the probe drives uniform …eddy currents in the plate and all the three spatial components of the perturbation electromagnetic field are sensed with a magnetic sensor. Influences of the crack's partial conductivity as well as its dimensions on the perturbation field's components are studied in order to enhance evaluation of real partially conductive cracks. Show more

Keywords: Non-destructive inspection, eddy-currents, perturbation field, partially conductive cracks, diagnosis

DOI: 10.3233/JAE-2012-1478

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 329-334, 2012

Authors: Pei, Cuixiang | Zhu, Haitao | Demachi, Kazuyuki | Sekino, Masaki | Uesaka, Mitsuru

Article Type: Research Article

Abstract: In a uniform magnetic field, objects with different magnetic susceptibility may cause magnetic field distortion that can be detected by magnetic resonance imaging (MRI). Conventional MRI techniques focus on magnitude image that shows dark signals at non-uniform magnetic field. However, it is difficult to obtain the magnetic susceptibility information just from the magnitude of signal. A post-processing method is proposed to measure the magnetic field gradient induced by the sample object. Both the polarity and …strength of magnetic field gradient can be calculated by this method. The method is proved by MRI experiments with paramagnetic material iron oxide particles at different concentrations, copper, and diamagnetic material graphite. Show more

Keywords: Magnetic resonance imaging, magnetic susceptibility, echo shift, local Fourier transform

DOI: 10.3233/JAE-2012-1479

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 335-340, 2012

Authors: Zaidi, H. | Santandrea, L. | Krebs, G. | Le Bihan, Y. | Demaldent, E.

Article Type: Research Article

Abstract: In this paper a new field of application of the overlapping finite element method is proposed for eddy current testing. This method, which has already been used to deal with the lift-off, is extended to the treatment of thin conducting and/or magnetic layers.

Keywords: Finite element method, dual formulations, eddy current testing, overlapping finite element

DOI: 10.3233/JAE-2012-1480

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 341-346, 2012

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

Article Type: Research Article

Abstract: The paper presents analyses and numerical validations of eddy current testing (ECT) algorithms used during In-Service Inspection (ISI) of ferromagnetic steam generator (SG) tubes of Fast Breeder Reactors (FBR). The purpose of such algorithms is to remove from ECT signal the electromagnetic noise resulting from sodium accumulated outside of SG tubes after SG vessel draining. Finite element method (FEM) simulations are used to analyse different sodium build-up scenarios observed experimentally, and to determine optimal …multi-frequency ECT algorithms to suppress the most efficiently sodium noise. A novel "window multi-frequency" algorithm is applied and validated using 3-dimensional FEM simulations of SP and sodium forms. Show more

Keywords: Steam generator, fast-breeder reactor, remote field eddy current, sodium, multi-frequency

DOI: 10.3233/JAE-2012-1481

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 347-353, 2012

Authors: Bernieri, Andrea | Betta, Giovanni | Ferrigno, Luigi | Laracca, Marco

Article Type: Research Article

Abstract: The paper proposes the use of a suitable multi-frequency approach applied to a novel instrument for eddy current non-destructive testing on conductive materials. The instrument is composed by a smart eddy current probe, based on a Giant Magneto Resistance sensor, and by a suitable processing unit. Key features of the proposed instrument are the capability of detecting, locating, and characterizing thin defects such as superficial and sub-superficial cracks. The proposed multi-frequency solution, together with a …suitable data processing, allow both the sensitivity in the defect detection to be increased and the ability to evaluate the defect characteristics in terms of shape and dimension to be improved. Show more

Keywords: Multifrequency Eddy Current Testing, GMR sensor, defect depth estimation

DOI: 10.3233/JAE-2012-1482

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 355-362, 2012

Authors: Bonavolontà, C. | Valentino, M. | Meola, C. | Carlomagno, G.M.

Article Type: Research Article

Abstract: The CNTs properties have inspired interest in using CNTs as a filler in polymer composite systems to obtain ultra-light structural materials with enhanced electrical, thermal and optical characteristics. In particular, industry recognizes many potential applications such as electrostatically dissipative materials, nano-sensors and aerospace structural materials. In this paper the eddy current based SQUID and the thermographic techniques have been used to study electromagnetic properties of nano-composite materials.

Keywords: Nano-composite, HTS SQUID, eddy current, thermography (LT), thermo-elastic

DOI: 10.3233/JAE-2012-1483

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 363-368, 2012

Authors: Tsunokai, Manabu | Takase, Kentaro | Kayata, Ryo | Nakano, Kenzo

Article Type: Research Article

Abstract: This paper proposes a new non-destructive method for evaluating the size of the flaking in ball bearing with an electromagnetic sensor. This method focuses on the variation of the magnitude of the characteristic frequency of a defect on the outer race. Through the presence of local maximums and minimums, the length of the flaking is evaluated while the bearing is in operation. The applicability and accuracy of this method is confirmed through several accelerated aging tests. …It is shown that the growth of the length of the flaking in ball bearings is linear. Show more

Keywords: Bearing defect, flaking, non-destructive diagnosis, electromagnetic sensor

DOI: 10.3233/JAE-2012-1484

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 369-373, 2012