Micro-plasticity and intermittent dislocation activity in a simplified micro-structural model

P. M. Derlet, R. Maaß

Research output: Contribution to journalArticlepeer-review

Abstract

Here we present a model to study the micro-plastic regime of a stress-strain curve. In this model an explicit dislocation population represents the mobile dislocation content and an internal shear-stress field represents a mean-field description of the immobile dislocation content. The mobile dislocations are constrained to a simple dipolar mat geometry and modelled via a dislocation dynamics (DD) algorithm, whilst the shear-stress field is chosen to be a sinusoidal function of distance along the mat direction. The sinusoidal function, defined by a periodic length and a shear-stress amplitude, is interpreted to represent a pre-existing micro-structure. These model parameters, along with the mobile dislocation density, are found to admit a diversity of micro-plastic behaviour involving intermittent plasticity in the form of a scale-free avalanche phenomenon, with an exponent and scaling-collapse for the strain-burst magnitude distribution that is in agreement with mean-field theory and similar to that seen in experiment and more complex DD simulations.

Original languageEnglish (US)
Article number035007
JournalModelling and Simulation in Materials Science and Engineering
Volume21
Issue number3
DOIs
StatePublished - Apr 2013
Externally publishedYes

ASJC Scopus subject areas

  • Modeling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Computer Science Applications

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