대한전자공학회논문지TE (Journal of the Institute of Electronics Engineers of Korea TE)

대한전자공학회 (The Institute of Electronics and Information Engineers)
권호 표지

최소극 문턱치 알고리즘을 이용한 고감쇠 용접부에서 초음파 검사방법에 관한 연구

A Study on the Ultrasonic Inspection Method in High Attenuation Welds using Minimization-Polarity Threshold Algorithm

  • 구길모 (한국원자력연구소 열수력 안전연구부) ;
  • 박치승 (카이텍(주) 기술연구소) ;
  • 최종호 (강남대학교 전자공학과) ;
  • 고덕영 (전주공업대학 전자과)
  • Koo, Kil-Mo (Heat-Water Power Safety Research Division, KAERI) ;
  • Park, Chi-Seung (Technical Research Institute, KAITEK) ;
  • Choi, Jong-Ho (Dept. of Elec. Eng., Kang-Nam University) ;
  • Ko, Duck-Young (Dept.of Elec. Eng., Jeon-Ju Technical College)
  • 발행 : 2000.09.01
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초록

본 논문에서는 결함신호의 신호 대 잡음비를 높이기 위해 최소진복선택 알고리즘과 극 문턱치(PT : polarity threshold) 알고리즘을 결합한 최소극 문턱치(MPO : minimum polarity threshold) 알고리즘을 이용한 원전 고감쇠 용접부 초음파 검사방법을 제안하였다. 제안된 알고리즘의 유용성을 확인하기 위한 실험에서는 ASME Xl 코드에 준하는 원전의 실제 모재와 동일한 용접방법으로 제작된 대비 시험편과 4종류의 개선된 탐촉자를 이용하였다. 실험 결과, SE(safeend)와 CCSS(centrifugal casting stainless steel) 재료는 조직의 구조적 특성 때문에 산란신호가 발생하고, 용접 내부에서는 높은 감쇠 현상이 발생하여 정확한 결합검출 능력이 저하되며, 이러한 결함신호에 최소극 문턱치 알고리즘을 적용하면 신호 대 잡음비가 2.6배 개선됨을 확인하였다.

In this paper, an ultrasonic testing method for inspection of high attenuation welding area using the minimum Polarity threshold algorithm which combines the minimum amplitude selection algorithm and polarity threshold algorithm is suggested to increase the signal to noise ratio of the flow signal. In order to confirm the usefulness of the suggested algorithm, experiments were performed using four probes and standard specimens following the ASME Xl Code. As a result, scattering signals were observed from the SE(safe end) and CCSS (centrifugal casting stainless steel) materials due to the microstructural characteristical, and the detectability was reduced due to the highly attenuated signal from the weldment area, but it was conformed that using the suggested algorithm, the signal to noise ratio increased about 2.6.

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참고문헌

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