Ductile failure analysis of API X65 pipes with notch-type defects using a local fracture criterion

Chang Kyun Oh, Yun Jae Kim, Jong Hyun Baek, Young Pyo Kim, Woo Sik Kim

Research output: Contribution to journalArticlepeer-review

106 Citations (Scopus)


A local failure criterion for API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed finite element (FE) analyses with the proposed local failure criterion, burst pressures of defective pipes are estimated and compared with experimental data. For pipes with simulated corrosion defects, FE analysis with the proposed local fracture criterion indicates that predicted failure takes place after the defective pipes attain maximum loads for all cases, possibly due to the fact that the material has sufficient ductility. For pipes with simulated gouge defects, on the other hand, it is found that predicted failure takes place before global instability, and the predicted burst pressures are in good agreement with experimental data, providing confidence in the present approach.

Original languageEnglish
Pages (from-to)512-525
Number of pages14
JournalInternational Journal of Pressure Vessels and Piping
Issue number8
Publication statusPublished - 2007 Aug
Externally publishedYes


  • API X65 steel
  • Ductile fracture
  • Finite element (FE) analysis
  • Gouge
  • Local fracture strain criterion

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


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