Attaining the rate-independent limit of a rate-dependent strain gradient plasticity theory

Salim Abdallah El-Naaman, Kim Lau Nielsen, Christian Frithiof Niordson

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Abstract

The existence of characteristic strain rates in rate-dependent material models, corresponding to rate-independent model behavior, is studied within a back stress based rate-dependent higher order strain gradient crystal plasticity model. Such characteristic rates have recently been observed for steady-state processes, and the present study aims to demonstrate that the observations in fact unearth a more widespread phenomenon. In this work, two newly proposed back stress formulations are adopted to account for the strain gradient effects in the single slip simple shear case, and characteristic rates for a selected quantity are identified through numerical analysis. Evidently, the concept of a characteristic rate, within the rate-dependent material models, may help unlock an otherwise inaccessible parameter space.
Original languageEnglish
JournalExtreme Mechanics Letters
Volume9
Issue numberPart 1
Pages (from-to)40-44
ISSN2352-4316
DOIs
Publication statusPublished - 2016

Keywords

  • Back stress formulation
  • Crystal plasticity
  • Rate-dependent theory
  • Size-effects
  • Strain gradient plasticity

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