Three-dimensional crack observation, quantification and simulation in a quasi-brittle material

M. Mostafavi*, N. Baimpas, E. Tarleton, R. C. Atwood, S. A. McDonald, A. M. Korsunsky, T. J. Marrow

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

45 Citations (Scopus)

Abstract

To investigate the fracture behaviour of polygranular graphite (a quasi-brittle material), crack propagation in a short bar chevron notched specimen was studied by synchrotron X-ray computed tomography combined with digital volume correlation. Displacements were measured within the loaded test specimen, particularly the three-dimensional (3-D) profile of crack opening displacement. Analysis of the 3-D displacement field confirmed the existence of distributed damage in a fracture process zone, which significantly increased the effective crack length. Finite element simulations affirmed that the measured crack opening profiles could be reproduced using a cohesive zone model, but not with a linear elastic analysis. Comparing the simulation to the experimental results, it was deduced that the critical strain energy release rate varied across the crack front, i.e. the fracture toughness is constraint-dependent. This is proposed to be a general characteristic of quasi-brittle materials.

Original languageEnglish
Pages (from-to)6276-6289
Number of pages14
JournalActa Materialia
Volume61
Issue number16
DOIs
Publication statusPublished - Sep 2013

Keywords

  • Cohesive zone model
  • Digital volume correlation
  • Fracture
  • Quasi-brittle
  • X-ray tomography

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