Modelling the surface roughness influence on the hole expansion ratio of multiphase steel

Research output: Contribution to journalConference articleScientificpeer-review

Researchers

  • S. Münstermann
  • P. Wechsuwanmanee
  • J. Lian

Research units

  • RWTH Aachen University

Abstract

There exist both extrinsic manufacturing process-related and intrinsic material-immanent effects on the edge crack sensitivity of dualphase steels. Extrinsic influences can be further divided into effects of residual damage as well as roughness-induced effects. A new simulation framework is applied to quantitatively assess the surface roughness-induced influences on the edge crack sensitivity of cold rolled dualphase steel of grade DP1000. Hole expansion ratios are numerically predicted for four different edge manufacturing processes, including drilling, milling, waterjet cutting, and wire cutting. The simulation framework applies the idea to make use of a ductile damage mechanics model. It employs realistic material parameters for all elements situated in the bulk, whereas those elements situated at the edge to be expanded during the test apply artificial model parameters. These are identified with the help of sub-models with geometrical surface representation. For the sub-model construction, roughness profiles are experimentally characterized by white light confocal microscopy. With the new simulation framework, numerical predictions of hole expansion ratios can be significantly improved, even though a remarkable overestimation still remains. Among others, this general overestimation can be attributed to local strain hardening, residual stresses, and microstructural modifications.

Details

Original languageEnglish
Article number012006
JournalIOP Conference Series: Materials Science and Engineering
Volume651
Issue number1
Publication statusPublished - 26 Nov 2019
MoE publication typeA4 Article in a conference publication
EventInternational Deep Drawing Research Group Annual Conference - Enschede, Netherlands
Duration: 3 Jun 20197 Jun 2019
Conference number: 38

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