Effect of bend angle on plastic loads of pipe bends under internal pressure and in-plane bending

Yun Jae Kim, Kuk Hee Lee, Chang Sik Oh, Bong Yoo, Chi Yong Park

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


This paper quantifies the effect of a bend angle of a pipe bend on plastic loads, via small strain and large strain finite element (FE) limit analyses using elastic-perfectly plastic materials. To consider the effect of the attached straight pipe, two limiting cases are considered. One case corresponds to the pipe bend without the attached straight pipe, and the other to that with a sufficiently long attached straight pipe. For the former case, the FE results suggest that the limit load is not affected by the bend angle for both in-plane bending and internal pressure. For the latter case, however, the bend angle affects plastic loads. An interesting finding is that the plastic load smoothly changes from the limit load of the straight pipe when the bend angle approaches zero to the plastic load of the 90{ring operator} pipe bend when the bend angle approaches 90{ring operator}. Based on such observations, closed-form plastic load solutions are proposed for the pipe bend with an arbitrary bend angle under in-plane bending and internal pressure.

Original languageEnglish
Pages (from-to)1413-1424
Number of pages12
JournalInternational Journal of Mechanical Sciences
Issue number12
Publication statusPublished - 2007 Dec

Bibliographical note

Funding Information:
This research is performed under the Program of Basic Atomic Energy Research Institute (BAERI), is a part of the Nuclear R & D Programs funded by the Ministry of Science and Technology (MOST) of Korea, and under the Program of the Brain Korea 21 Project in 2006. The authors also wish to acknowledge valuable comments from reviewers.


  • Bend angle
  • Finite element limit analysis
  • Large geometry change
  • Pipe bend
  • Plastic load
  • Small geometry change

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Aerospace Engineering
  • Ocean Engineering
  • Applied Mathematics
  • General Materials Science
  • Civil and Structural Engineering


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