A generalized damage model accounting for instability and ductile fracture for sheet metals

Junhe Lian*, Xiaoxu Jia, Sebastian Münstermann, Wolfgang Bleck

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

11 Citations (Scopus)

Abstract

With the requirement of vehicle performance and fuel economy, dual-phase (DP) steels as one of the advanced high stress steels (AHSS) are increasingly used in the automotive industry due to the excellent combination of the tensile strength and ductility. On a microscale the ductile fracture is governed by the void nucleation, growth and coalescence mechanism. In the dual-phase steels this damage mechanism exhibits a rather complex situation: voids are generated by the debonding of the hard phase from the matrix and the inner cracking of the hard phase besides by inclusions. On a macroscale fracture of these materials is observed in the automotive industry with the absence of strain localization or minimal post-necking deformation. Consequently the failure during the forming process is caused by a competitive or combined mechanism of internal damage evolution and metal instability. In this study, the target is to develop a simple and generalized model for metal forming processes accounting for instability, damage and ductile fracture. Theoretical predictions of metal instability by the Hill-Swift necking criterion and the modified maximum force criterion are considered. The damage model is developed by the combination of the prediction of metal instability and ductile fracture of sheet metals. The model is developed in 3D triaxial stress state and the accumulation of damage is stress state dependent. Furthermore, the influence of the hardening curve effected by damage on the forming limit curve is investigated.

Original languageEnglish
Title of host publicationMaterial Forming ESAFORM 2014
PublisherTrans Tech Publications Ltd.
Pages106-110
Number of pages5
ISBN (Print)9783038351061
DOIs
Publication statusPublished - 1 Jan 2014
MoE publication typeA4 Article in a conference publication
EventInternational ESAFORM Conference on Material Forming
- Espoo, Finland
Duration: 7 May 20149 May 2014
Conference number: 17

Publication series

NameKey Engineering Materials
Volume611-612
ISSN (Print)1013-9826

Conference

ConferenceInternational ESAFORM Conference on Material Forming
Abbreviated titleESAFORM
Country/TerritoryFinland
CityEspoo
Period07/05/201409/05/2014

Keywords

  • DP steel
  • Hill-Swift necking criterion
  • Hybrid damage plasticity model
  • Localization
  • MBW model
  • Modified maximum force criterion

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