A unified model for deformation instability based on energy inflection

Bo Hu, Q. Wei, Yulong Li, Yazhou Guo

Research output: Contribution to journalArticlepeer-review

Abstract

The critical state of plastic instability preceding the fracture of metals, such as necking under tension and shear banding under torsion, was carefully analyzed from thermodynamics considerations. A unified criterion based on energy inflection (EI criterion) was established which takes stress states and loading rates into account. Different from many other criteria that are based on a specified energy, the proposed criterion assumes deformation instability would occur at the point of energy inflection. Through calibrating the parameters that governed the entropy evolution, the EI criterion was shown to exhibit significant efficacy in predicting the critical strain at which instability occurred for Ti-6Al-4V, aluminum alloy, and pure copper under various loading conditions. Furthermore, a comparison of the proposed EI criterion was made with other criteria in the literature.

Original languageEnglish
Article number109372
JournalInternational Journal of Mechanical Sciences
Volume276
DOIs
StatePublished - 15 Aug 2024

Keywords

  • Deformation instability
  • Energy inflection
  • Loading rates
  • Stress states
  • Unified model

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