A fatigue crack initiation model incorporating discrete dislocation plasticity and surface roughness

Steffen Brinckmann*, Erik Van der Giessen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Although a thorough understanding of fatigue crack initiation is lacking, experiments have shown that the evolution of distinct dislocation distributions and surface roughness are key ingredients. In the present study we introduce a computational framework that ties together dislocation dynamics, the fields due to crystallographic surface steps and cohesive surfaces to model near-atomic separation leading to fracture. Cyclic tension-compression simulations are carried out where a single plastically deforming grain at a free surface is surrounded by elastic material. While initially, the cycle-by-cycle maximum cohesive opening increases slowly, the growth rate at some instant increases rapidly, leading to fatigue crack initiation at the free surface and subsequent growth into the crystal. This study also sheds light on random local microstructural events which lead to premature fatigue crack initiation.

Original languageEnglish
Pages (from-to)155-167
Number of pages13
JournalInternational Journal of Fracture
Volume148
Issue number2
DOIs
Publication statusPublished - Nov-2007

Keywords

  • dislocation
  • cohesive surface
  • surface roughness
  • fatigue initiation
  • SINGLE-CRYSTALS
  • MICROMECHANICAL MODEL
  • GROWTH
  • DYNAMICS
  • COPPER
  • LOCALIZATION
  • DEFORMATION
  • SIMULATIONS
  • NUCLEATION
  • STRAIN

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