Transactions of the Korean Society of Pressure Vessels and Piping (한국압력기기공학회 논문집)

Korean Society of Pressure Vessels and Piping (한국압력기기공학회)
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Estimations of Strain-Based J-integral and CTOD for Circumferential Outer Surface Crack in the Weld of Gas Pipeline Under Axial Displacement

축방향 변위가 작용하는 가스 파이프라인 용접부에 존재하는 원주방향 외부표면균열의 변형률 기반 J-적분 및 CTOD 계산

  • 김경민 (서울과학기술대학교 기계시스템디자인공학과) ;
  • 박지수 (서울과학기술대학교 기계시스템디자인공학과) ;
  • 문지희 (서울과학기술대학교 기계시스템디자인공학과) ;
  • 장윤영 (서울과학기술대학교 기계시스템디자인공학과) ;
  • 박승현 (성균관대학교 기계공학부) ;
  • 허남수 (서울과학기술대학교 기계시스템디자인공학과)
  • Received : 2020.05.27
  • Accepted : 2020.06.22
  • Published : 2020.06.30
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Abstract

Pipelines subjected to ground movement would be easily exposed to large-scale deformation. Since such deformations may cause the pipeline failure, it is important to ensure the safety of pipelines in various operation conditions. However, crack in weld metal have been considered as one of the main causes that can deteriorate the structural integrity of the pipeline. For this reason, the structural integrity of the pipe containing the crack in the weld should be obtained. In order to assess cracked pipe, J-integral and crack-tip opening displacement(CTOD) have been applied widely as the elastic-plastic fracture mechanics parameters representing crack driving force. In this study, engineering solutions to calculate the J-integral and CTOD of pipes with a circumferential outer surface crack in the weld are proposed. For this purpose, 3-dimensional elastic-plastic finite element(FE) analyses have been performed considering the effect of overmatch and width of weld. The shape of the weld was simplified to I-groove, and axial displacement was employed as for loading condition. Based on FE results, the effects of crack size, material properties and width of weldment on J-integral and CTOD were investigated. Additionally, the J-integral and CTOD for I-groove were compared with those for V-groove to examine the effects of the weld shape, and a proportionality coefficient of J-integral and CTOD was calculated from the results of this paper.

Keywords

References

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