Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Development of an SH Wave Magnetostrictive Transducer Module for Guided Wave Testing of Plate Structures

판형 구조물 유도초음파 검사를 위한 SH파 자기변형 트랜스듀서 모듈 개발

  • Cho, Seung-Hyun (Center for Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Park, Jae-Ha (Center for Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Kwon, Hyu-Sang ;
  • Ahn, Bong-Young (Center for Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Lee, Seung-Seok (Center for Safety Measurement, Korea Research Institute of Standards and Science)
  • 조승현 (한국표준과학연구원 안전측정센터) ;
  • 박재하 (한국표준과학연구원 안전측정센터) ;
  • 권휴상 (한국표준과학연구원 유동음향센터) ;
  • 안봉영 (한국표준과학연구원 안전측정센터) ;
  • 이승석 (한국표준과학연구원 안전측정센터)
  • Published : 2009.04.30
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Abstract

Recently much attention has been paid to a guided wave due to its effective applicability to long range and fast inspection of structures. In guided wave based NDE, the appropriate selection of wave modes is one of important factors since the test performance is highly dependent on which mode of guided waves is employed. As far as plate-like structures are concerned, so far, SH guided wave has not been frequently applied compared to Lamb waves, which is mostly caused by the lack of proper and convenient transducers to generate and measure the SH waves. In this investigation, a new small-sized SH guided wave transducer based on magnetostriction is proposed. The present transducer was designed to be modular and be used with shear couplant to avoid the inconvenience of the existing magnetostrictive patch transducers, which comprises the ferromagnetic patch tightly bonded to a structure. The wave transduction mechanism and the detailed configuration of the present transducer are presented. Experimental verification is also conducted on test specimens and the results confirm the good performance of the present transducer module.

유도초음파 검사는 구조물의 장거리 탐상 적용 가능성으로 인해 최근 많은 주목을 받고 있다. 이러한 유도초음파를 이용한 비파괴검사에 있어서 탐상 성능은 검사시 이용하는 유도초음파 모드에 많은 영향을 받기 때문에 탐상 목적에 맞는 적절한 모드를 선택하는 것이 매우 중요하다. 판형 구조물 검사의 경우, 현재까지 램파가 주로 이용되어 왔고 SH파의 응용은 상대적으로 적었다. SH파의 장점에도 불구하고 응용 빈도가 적은 것은 무엇보다도 성능이 검증되면서 사용이 용이한 트랜스듀서가 부족한 데 주 원인이 있다. 본 연구에서는 자기변형 현상을 이용한 새로운 소형 SH파 유도초음파 트랜스듀서 모듈을 제안하고자 한다. 기존의 SH파용 자기변형 트랜스듀서가 패치를 구조물에 접착제로 부착해서 사용해야하는 점으로 인해 많은 불편을 초래한 데 비해, 제안한 트랜스듀서는 모듈로 제작되어 전단커플런트와 함께 이용할 수 있으므로 현장에서 신속하고 편리하게 적용이 가능하다. 개발된 트랜스듀서 모듈의 SH파 변환 기전과 구조를 설명하였으며, 이를 이용한 유도초음파 전파 시험을 통해 제안한 트랜스듀서 모듈의 성능 및 응용가능성을 확인하였다.

Keywords

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