Modeling of plasticity and fracture behavior of X65 steels : seam weld and seamless pipes

Marcelo Paredes*, Junhe Lian, Tomasz Wierzbicki, Mihaela E. Cristea, Sebastian Münstermann, Philippe Darcis

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

21 Citations (Scopus)


A non-associated/associated flow rule coupled with an anisotropic/isotropic quadratic yield function is presented to describe the mechanical responses of two distinct X65 pipeline steels. The first as a product of the cold-rolling forming (UOE) process also known as seam weld pipes and the second as a result of high temperature piercing process called seamless tube manufacturing. The experimental settings consist of a wide range of sample types, whose geometric characteristics represent different state of stresses and loading modes. For low to intermediate stress triaxiality levels, flat specimens are extracted at different material orientations along with notched round bar samples for high stress triaxialities. The results indicate that despite the existing differences in plasticity between materials due to anisotropy induced processes, material failure can be characterized by an isotropic weighting function based on the modified Mohr–Coulomb (MMC) criterion. The non-associated flow rule allows for inclusion of strain directional dependence in the definition of equivalent plastic strain by means of scalar anisotropy (Lankford) coefficients and thus keeping the original capabilities of the MMC model.

Original languageEnglish
Pages (from-to)17-36
Number of pages20
JournalInternational Journal of Fracture
Issue number1
Early online date1 Jan 2018
Publication statusPublished - 1 Sep 2018
MoE publication typeA1 Journal article-refereed


  • Anisotropic behavior
  • Modeling plasticity
  • Seam weld pipe
  • Seamless pipe
  • X65 steels


Dive into the research topics of 'Modeling of plasticity and fracture behavior of X65 steels : seam weld and seamless pipes'. Together they form a unique fingerprint.

Cite this