DOI QR코드

DOI QR Code

철-코발트 합금 패치로 구성된 자기변형 트랜스듀서를 이용한 체적 전단파 발생 및 측정

Bulk Shear-Wave Transduction Experiments Using Magnetostrictive Transducers with a Thin Fe-Co Alloy Patch

  • 박재하 (한국표준과학연구원 안전측정센터) ;
  • 조승현 (한국표준과학연구원 안전측정센터) ;
  • 안봉영 (한국표준과학연구원 안전측정센터) ;
  • 권휴상 (한국표준과학연구원 유동음향센터)
  • Park, Jae-Ha (Center for Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Cho, Seung-Hyun (Center for Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Ahn, Bong-Young (Center for Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Kwon, Hyu-Sang (Center for Fluid Flow and Acoustics, Korea Research Institute of Standards and Science)
  • 투고 : 2010.03.16
  • 심사 : 2010.07.02
  • 발행 : 2010.08.01

초록

최근 가공성이 우수하고 강한 자기변형성을 가진 강자성 패치가 소개되면서, 이를 이용한 탄성초음파 변환 연구가 활발하다. 이러한 자기변형 패치 트랜스듀서는 SH 파와 비틀림파 등 전단파 변환 성능이 우수하여 비파괴평가 분야에서 많은 주목을 받고 있지만, 지금까지 관련 연구가 유도초음파 변환에 집중된 반면 체적초음파에는 아직 적용이 된 예가 없다. 본 연구에서는, 자기변형성이 큰 재질 중 하나인 철-코발트 합금을 이용한 체적전단파 트랜스듀서를 제안하고자 한다. 제안한 트랜스듀서는 강자성 패치, 코일, 영구자석, 요크를 포함하여 모듈형으로 설계되었고, 실험을 통해서 파형 및 방사 패턴 등을 측정하였다. 결과적으로, 제안한 트랜스듀서는 신호대잡음비 및 방사패턴 면에서 상당히 우수한 성능을 보임을 확인하였다.

Recently, the results of many studies have clarified the successful performance of magnetostrictive transducers in which a ferromagnetic patch is used for the transduction of guided shear waves; this is because a thin ferromagnetic patch with strong magnetostriction is very useful for generating and detecting shear wave. This investigation deals with bulk shear wave transduction by means of magnetostriction; on the other hand, the existing studies have been focused on guided shear waves. A modular transducer was developed; this transducer comprised a coil, magnets, and a thin ferromagnetic patch that was made of Fe-Co alloy. Some experiments were conducted to verify the performance of the developed transducer. Radiation directivity pattern of the developed transducer was obtained, and a test to detect the damage on a side drill hole of a steel block specimen was carried out. From the results of these tests, the good performance of the transducer for nondestructive testing was verified on the basis of the signal-to-noise ratio and narrow beam directivity.

키워드

참고문헌

  1. Joule, J. P., 1847, “On the Effect of Magnetism upon the Dimensions of Iron and Steel Bars,” Phi. Mag. III, Vol. 30, p. 76. https://doi.org/10.1080/14786444708645656
  2. Villari, E., 1865, “Change of Magnetization by Tension and by Electric Current,” Ann. Phy. Chem., Vol. 126, pp. 87-122.
  3. Kwun, H., 2002, “Method and Apparatus Generating and Detecting Torsional Wave Inspection of Pipes or Tubes,” U.S Patent, Patent No. 6429650 B1.
  4. Kim, Y. Y., Park, C. I., Cho, S. H. and Han, S. W., 2005, “Torsional Wave Experiments with a New Magnetostrictive Transducer Configuration,” J. Acoust. Soc. Am., Vol. 117, No. 6, pp. 3459-3468. https://doi.org/10.1121/1.1904304
  5. Cho, S. H., Lee, J. S. and Kim, Y. Y., 2006, “Guided Wave Transduction Experiment Using a Circular Magnetostrictive Patch and a Figure-of-Eight Coil in Nonferromagnetic Plates,” Applied Physics Letters, Vol. 88, 224101. https://doi.org/10.1063/1.2205724
  6. Park, C. I., Cho, S. H. and Kim, Y. Y., 2006, “Z-Shaped Magnetostrictive Patch for Efficient Transduction of a Torsion Wave Mode in a Cylindrical Waveguide,” Applied Physics Letters, Vol. 89, 174103. https://doi.org/10.1063/1.2369538
  7. Cho, S. H., Han, S. W., Park, C. I. and Kim, Y. Y., 2006, “Noncontact Torsional Wave Transduction in a Rotating Shaft Using Oblique Magnetostrictive Strips,” Journal of Applied Physics, Vol. 100, 104903. https://doi.org/10.1063/1.2386942
  8. Cho, S. H., Han, S. W., Park, C. I. and Kim, Y. Y., “High-Frequency Torsional Modal Testing of a Long Cylinder by Magnetostriction,” Applied Physics Letters, Vol. 91, 071908. https://doi.org/10.1063/1.2769400
  9. Cho, S. H., Park, J. H., Kwon, H. –S., Ahn, B. and Lee, S. S, 2009, “Development of an SH Wave Magnetostrictive Transducer Module for Guided Wave Testing of Plate Structures,” Journal of Korean Society for Nondestructive Testing, Vol. 29, No. 5, pp. 427-435.
  10. Cho, S. H., Park, J. H., Kwon, H. –S., Ahn, B. and Lee, S. S., 2009, “Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure,” Journal of Korean Society for Nondestructive Testing, Vol. 29, No. 5, pp. 427-435.
  11. http://www.cartech.com.
  12. Bozorth, R. M., 1993, Ferromagnetism, IEEE Press, New York.
  13. Jiles, D. C., 1995, Introduction to Magnetism and Magnetic Materials, Chapman & Hall, London.
  14. Thompson, R. B, 1979, “Generation of Horizontally Polarized Shear Waves in Ferromagnetic Materials Using Magnetostrictively Couples Meander-Coil Electromagnetic Transducers,” Applied Physics Letters, Vol. 34, pp. 175-177. https://doi.org/10.1063/1.90719
  15. Lee, J. S., Kim, Y. Y. and Cho, S. H., 2009, “Beam-Focused Shear Horizontal Wave Generation in a Plate by a Circular Magnetostrictive Patch Transducer Employing a Planar Solenoid Array,” Smart Materials and Structures, Vol. 18, 015009. https://doi.org/10.1088/0964-1726/18/1/015009