A study of the stress intensity factor and crack opening displacement relationship between uniform thickness pipe bends and non-uniform thickness pipe bends

Kyung Dong Bae, Chul Goo Kim, Seung Jae Kim, Hyun Jae Lee, Yun Jae Kim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper proposes the relationship of stress intensity factor and crack opening displacement between pipe bends with uniform thickness and those with non-uniform thickness. In actual case, pipe bends have thickness variations. Unlike typical pipe bends, heat induction bend pipes have significant thickness variations (non-uniform thickness) because of manufacturing process. When the ratio of radius of curvature and pipe radius is 3 for heat induction bend pipes, the thickness at intrados and extrados can be calculated by 1.75 times and 0.875 times of nominal thickness which is original thickness before manufacturing process, respectively. In this situation, it is difficult to apply existing elastic stress intensity factor and crack opening displacement results [1, 2] and it is essential to modify existing solution or to create new solution. In this paper, to find effect of pipe bends thickness variation, 90° through-wall cracked pipe bends with not only uniform thickness but also non-uniform thickness are considered. The ratios of radius and thickness are 5, 10 and ratios of pipe radius of curvature and radius are 3, 4 and 5. Loading condition is inplane opening bending for intrados crack and closing bending for extrados crack. The through-wall crack sizes are 12.5%, 25% and 37.5% of circumferential cross section. Material of pipe bends is assumed to follow elastic behavior. The proposal is made by extensive finite elements analyses using ABAQUS [3], predicted elastic stress intensity factors for pipe bends with non-uniform thickness are compared with finite element results. The results show a good agreement. It may be useful to calculate elastic stress intensity factor for bends with nonuniform thickness without complex modeling and finite analyses.

Original languageEnglish
Title of host publicationMaterials and Fabrication
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791850428
DOIs
Publication statusPublished - 2016
EventASME 2016 Pressure Vessels and Piping Conference, PVP 2016 - Vancouver, Canada
Duration: 2016 Jul 172016 Jul 21

Publication series

NameAmerican Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
Volume6A-2016
ISSN (Print)0277-027X

Other

OtherASME 2016 Pressure Vessels and Piping Conference, PVP 2016
Country/TerritoryCanada
CityVancouver
Period16/7/1716/7/21

Bibliographical note

Funding Information:
This work was supported by the Energy Efficiency & Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20131520202170)

Publisher Copyright:
Copyright © 2016 by ASME.

ASJC Scopus subject areas

  • Mechanical Engineering

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