Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Evaluation of the J integral of a CT specimen by FEM

FEM에 의한 CT시험편의 J 적분 해석에 관한 연구

  • Kim, Won Beom (Department of Naval Architecture and Ocean Engineering, Faculty of Mechanical Engineering, Ulsan College)
  • 김원범 (울산과학대학교 기계공학부 조선해양전공)
  • Received : 2014.10.15
  • Accepted : 2014.11.06
  • Published : 2014.11.30
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Abstract

In steel structures, including ships and offshore structures, defects induced during construction or in use causes cracks and damages. Calculation of the stress intensity factor (SIF) K is one method for crack analysis by fracture mechanics approach. In this paper, an evaluation of K was carried out using the J integral. In particular, in this study, a CT specimen was used to calculate the J integral. In the evaluation, 859 nodes and 1618 elements were used for the J integral calculation of the CT specimen by the in-house FEM program. A comparison of the result with the ASTM formula showed that the results from the current research of the J integral was in the 99% coincidence interval. Overall, cracks in this study can be studied satisfactorily by the J integral from the above mesh size.

선박 해양플랜트를 비롯한 강구조물에서는 건조중 형성된 결함이나 사용중에 가해지는 여러 가지 하중등에 의하여 균열을 비롯한 손상이 발생한다. 따라서 균열의 해석을 위하여 균열의 세기를 여러 가지 방법으로 평가하며, 파괴역학적 수법에 의한 응력확대계수 K도 그 중의 한가지 방법이다. 본 연구에서는 이러한 목적으로 사용되는 강구조물용 강재의 응력확대계수 K의 평가를 위하여 특히 CT시험편에 대하여 J 적분을 사용하여 평가를 실시하였다. CT시험편의 J 적분의 평가에는 inhouse FEM program을 사용하였으며, 859개의 node 와 1618개의 element로 해석을 실시하였다. 계산결과 본 연구에서의 해석결과는 ASTM에서 제시하는 식에 의한 K값과 99%정도의 일치도를 나타내었다. 이상으로부터 본 연구에서의 시험편에 대하여 사용한 mesh size로 충분한 정도의 균열 해석이 가능함을 알 수 있었다.

Keywords

References

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