• Title/Summary/Keyword: Magnetostrictive Vibration

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Development and Application of Phased Array System for Defect Imaging in Plate-like Structures (평판 구조물의 영상화를 위한 위상 배열 시스템 개발 및 응용)

  • Lee, Joo Kyung;Kwon, Young Eui;Lee, Heung Son;Seung, Hong Min;Kim, Ki Yeon;Lee, Jun Kyu;Kim, Hoe Woong;Lee, Ho Cheol;Kim, Yoon Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.2
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    • pp.123-130
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    • 2014

  • An ultrasonic magnetostrictive transducer-based phased-array system for imaging defects in plate structures is newly proposed. In that most ultrasonic phased array systems rely on piezoelectric transducers or electromagnetic acoustic transducers, this system has its own unique feature of employing magnetostrictive transducers. Interest in using a phased array system using magnetostrictive transducers has been recently reported for pipe inspection but no such system has been developed for plate inspection. In this investigation, we aim to propose a phased array system using OL-MPTs (Omnidirectional Lamb wave Magnetostrictive Patch Transducers) for plate inspection. The developed system consists of a multi-channel function generator, power amplifiers, preamplifiers and a data acquisition unit. In the process of its development, each of the units must be checked and in doing so, we suggest types of ultrasonic wave experiments that should be carried out. Finally, the phased system using a transducer array composed of eight OL-MPTs is newly configured and is applied for actual crack detection experiments.

  • https://doi.org/10.5050/KSNVE.2013.24.2.123 인용 PDF KSCI KPUBS HTML

Study on the Elimiation of Irreversible Magnetic Components Using Anhysteretization in a Magnetostrictive Vibration Sensor (자왜형 진동 센서의 비이력화를 통한 비가역적 자화성분 제거에 관한 연구)

  • Lee, Ho-Cheol;Bae, Won-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.9
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    • pp.841-848
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    • 2010

  • Previous experimental results show that the magnetostrictive transducer has the peculiar characteristic with relation to their reversible magnetization and its practical usage will be hindered by this phenomena. In this paper, the idea of anhysteretization is adopted in order to solve this problem. The experimental results reveal that the anhysteretization can get rid of the extraordinary phenomena which are occurred by the change of biasing magnetic field. The effects of two important parameters, which are the amplitude and the decaying time of this process, on the anhysteretization are investigated experimentally. Finally the best operating condition is proposed in order to maximize the sensitivity under the anhysteretization.

  • https://doi.org/10.5050/KSNVE.2010.20.9.841 인용 PDF KSCI

A Study of the Low Noise Transformer by Avoiding the Structural Resonance (구조 공진회피에 의한 변압기 소음저감)

  • Choi, Won-Ho;Kim, Jin;Suk, Ho-Il
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.12
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    • pp.520-526
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    • 2005

  • Demands for the noise reduction of a transformer has been becoming an common issue because it has been used mainly at the residence area such as an apartment complex. This paper shows 2 trouble shooting examples that high noise sources were found out structural resonance of a transformer by 120Hz exciting frequency caused from magnetostrictive vibration of core. This paper presents that vibration data are very important to find noise source and how to avoid natural frequency of core and tank wall

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Design and Fabrication of Magnetostrictive Transducers for Scanning OPMT Development (주사형 OPMT 개발을 위한 자왜형 초음파 변환기 설계 및 제작)

  • Lee, Ho-Cheol;Kim, Hyeng-Yoon;Kim, Y.Y.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.856-859
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    • 2005

  • The OPMT(Orientation-adjustable Patch-type Magnetostrictive Transducer) was proposed as a tool for generating and measuring the ultrasonic Lamb wave in plate type structures. This sensor has a lot of new features compared to the traditional piezo-type ultrasonic transducers. As an example, it does not need any kind of wiring for lunching or measuring ultrasonic waves. But it has also definite limitation for practical usage as a nondestructive testing tool in that it cannot help rotating the direction of ultrasonic wave manually. The idea for 'scanning OPMT' is proposed in this respect. Two kinds of basic ideas for rotating the wave direction not manually but electrically are proposed. The fabrication of the transducer and the testing for Identifying the primary characteristics are done for one of the proposed transducers. The results says that there are the possibilities as a new tool for NDE in that the proposed transducer follows well the characteristics of the traditional OPMT. But there are also the 1imitations to overcome.

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