Use of elastic follow-up to study the effect of displacement controlled loading on plastic collapse pressures for circumferentially cracked pipes

Guiyi Wu*, David J Smith, Martyn J Pavier

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

431 Downloads (Pure)

Abstract

Structural integrity assessments of pressurised pipes consider plastic collapse as a potential failure mode. This paper uses finite element analysis to explore the effect of the pipe end boundary conditions on the collapse pressure. Two end conditions are considered: a fixed axial load and a fixed axial displacement. The fixed axial displacement condition represents a long-range axial residual stress. In the R6 structural integrity assessment procedure long-range residual stress is associated with elastic follow-up. However, no guidance is given on whether the level of elastic follow-up is sufficient to justify treating long-range residual stress as a primary stress. In this paper, a method is proposed to estimate elastic follow-up of an internally pressurised pipe containing a fully circumferential crack. It is found that the elastic follow-up is related to the length of the pipe. A short pipe that contains a fully circumferential crack, subjected to a displacement induced axial stress, has a global collapse that is not modified by the fixed displacement condition. The short pipe corresponds to a small elastic follow-up factor, Z. However, as the elastic follow-up factor increases, the presence of long-range residual stress starts to make a contribution to global collapse. When elastic follow-up is significant, a long-range residual stress has the same effect on global collapse as does a mechanical stress.
Original languageEnglish
Title of host publicationASME 2015 Pressure Vessels and Piping Conference
Subtitle of host publicationMaterials and Fabrication
Place of PublicationBoston, Massachusetts, USA
PublisherAmerican Society of Mechanical Engineers (ASME)
Number of pages10
Volume6B-2015
ISBN (Print)9780791857007
DOIs
Publication statusPublished - 19 Jul 2015
EventASME 2015 Pressure Vessels and Piping Conference, PVP 2015 - Boston, United States
Duration: 19 Jul 201523 Jul 2015

Conference

ConferenceASME 2015 Pressure Vessels and Piping Conference, PVP 2015
CountryUnited States
CityBoston
Period19/07/1523/07/15

Keywords

  • pipes
  • collapse
  • displacement

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