Journal of the Computational Structural Engineering Institute of Korea (한국전산구조공학회논문집)

Computational Structural Engineering Institute of Korea (한국전산구조공학회)
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Modal Property Estimation of Tapered Cantilever Pipe-type Cracked Beam

테이퍼 캔틸레버 원형강관 균열보의 모드특성 추정

  • Lee, Jong Won (Department of Architectural Engineering, Namseoul Univ.) ;
  • Kim, Sang Ryul (Mechanical Systems Safety Research Division, Korea Institute of Machinery and Materials) ;
  • Kim, Bong Ki (Mechanical Systems Safety Research Division, Korea Institute of Machinery and Materials)
  • 이종원 (남서울대학교 건축공학과) ;
  • 김상렬 (한국기계연구원 기계시스템안전연구본부) ;
  • 김봉기 (한국기계연구원 기계시스템안전연구본부)
  • Received : 2014.04.14
  • Accepted : 2014.08.22
  • Published : 2014.10.31
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Abstract

Modal properties for tapered cantilever pipe-type beam is identified by applying the boundary conditions to a general solution for tapered beam. A bending stiffness for cracked beam is constructed based on an energy method for tapered cantilever thin-walled pipe, which has a through-the-thickness crack, subjected to bending. Then the natural frequencies and mode shapes of a tapered cantilever thin-walled cracked pipe are identified. It can be found that the phenomenon of the bending stiffness distribution along the beam length of the cracked beam is quite reasonable, the natural frequencies are decreased as the crack sizes are increased, and the mode shapes are changed due to the crack. This results may be used to the vibration-based crack identification for the tapered cantilever pipe-type tower structures.

본 연구에서는 테이퍼 보에 대한 미분방정식의 일반해에 캔틸레버 보의 경계조건을 적용하여 모드특성을 추정한다. 또한, 휨을 받는 테이퍼 원형강관 캔틸레버 보에 발생하는 관통균열을 모델링하기 위하여 에너지 방법을 이용하여 균열보에 대한 보 길이방향 휨강성을 구한 후 이를 이용하여 테이퍼 원형강관 캔틸레버 균열보에 대한 고유주파수와 모드형상을 추정한다. 보 길이에 따른 균열보의 휨강성 변화는 기존 연구에서 밝혀진 현상과 유사하게 합리적인 양상을 보였으며, 유도한 휨강성을 적용하여 산정한 균열보의 고유주파수는 균열 크기가 증가할수록 감소함을 확인하였고, 모드형상은 균열발생에 의해 변화함을 알 수 있었다. 연구결과는 향후 테이퍼 원형강관 캔틸레버 보 형태의 타워 구조물에 대한 진동기반 균열탐지에 활용될 수 있을 것으로 판단된다.

Keywords

References

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