Numerical determination of the damage parameters of a dualphase sheet steel

Ole West*, Junhe Lian, Sebastian Münstermann, Wolfgang Bleck

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

31 Citations (Scopus)

Abstract

Dual-phase steels show complex damage mechanisms that complicate the prediction of sheet formability. The ductile crack initiation locus (DCIL) has been developed as a failure criterion to better describe the characteristic forming behaviour in dual-phase steels. It displays the equivalent plastic strain at a critical combination of stress triaxiality and Lode angle with four damage parameters. Due to the high experimental complexity of the determination of these parameters and the missing link to the microstructure, an alternative numerical approach is of great interest. In this study, the micromechanical Gurson-Tvergaard- Needleman (GTN) model was employed to predict the damage parameters of a dual-phase steel. An adequate calibration procedure of the GTN parameters was defined with the consideration of the link between microstructural features and mechanical behaviours. After the determination of the GTN parameters, tensile tests of different specimens expressing different stress states were simulated using the GTN model. An overall good agreement was obtained for the force-displacement response. However, due to the exclusion of the Lode angle effect of the GTN model, the limitation of the capability of predicting the damage parameters in the whole stress state was also indicated and discussed.

Original languageEnglish
Pages (from-to)743-752
Number of pages10
JournalISIJ International
Volume52
Issue number4
DOIs
Publication statusPublished - 27 Apr 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • Ductile crack initiation
  • Lode angle
  • Micromechanical models
  • Parameter calibration
  • Unit cell

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