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Development of Design Formulas for Pipe Loops Used in Ships Considering the Structural Characteristics of Curved Portions

곡선부의 구조 특성을 고려한 선박용 파이프 루프 설계식 개발

Park, Chi-Mo;Bae, Byoung-Il
박치모;배병일

  • Received : 2012.09.11
  • Accepted : 2012.10.25
  • Published : 2012.10.31

Abstract

Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.

Keywords

Pipe loop;Design formula;Curvature of corners;Bending deformation correction factor;Bending stress correction factor;Finite element analysis

References

  1. MSC.Nastran 2005, Quick Reference Guide: Volume 1, 2, MSC. Software Corporation.
  2. 박치모, 배병일 (2010). "선박용 파이프 루프 곡선부의 구조해석에 관한 연구", 한국해양공학회지, 제24권, 제5호, pp 88-93.
  3. 박치모, 배병일 (2011). "선박 해양구조물 파이프 루프 곡선부 의 응력해석", 한국해양공학회지, 제25권, 제5호, pp 52-57.
  4. ABS(American Bureau of Shipping) (2008). Rules for Building and Classing Steel Vessels, Part 4, Chapter 6, Section 2, pp 389.
  5. JIS(Japanese Industrial Standard) (1988). JIS G 3454-1988; Carbon Steel Pipes for Pressure Service.
  6. Lloyd's Register (2006). Ship Piping Systems, Part 5, Chapter 13, Section 2, pp 3-4.
  7. 박치모, 양박달치 (2009). "코너부 곡률을 고려한 선박용 파이 프루프 설계식 개발", 한국해양공학회지, 제23권, 제4호, pp 91-99.

Acknowledgement

Supported by : 울산대학교