Strain gradient crystal plasticity effects on flow localization

Ulrik Borg

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In metal grains one of the most important failure mechanisms involves shear band localization. As the band width is small, the deformations are affected by material length scales. To study localization in single grains a rate-dependent crystal plasticity formulation for finite strains is presented for metals described by the reformulated Fleck-Hutchinson strain gradient plasticity theory. The theory is implemented numerically within a finite element framework using slip rate increments and displacement increments as state variables. The formulation reduces to the classical crystal plasticity theory in the absence of strain gradients. The model is used to study the effect of an internal material length scale on the localization of plastic flow in shear bands in a single crystal under plane strain tension. It is shown that the mesh sensitivity is removed when using the nonlocal material model considered. Furthermore, it is illustrated how different hardening functions affect the formation of shear bands.
Original languageEnglish
JournalInternational Journal of Plasticity
Volume23
Issue number8
Pages (from-to)1400-1416
ISSN0749-6419
DOIs
Publication statusPublished - 2007

Keywords

  • strain gradient plasticity
  • shear band
  • crystal plasticity

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