Geometry‐Dependent R‐Curve for Quasi‐Brittle Materials

Chengsheng Ouyang*, Surendra P Shah

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Fracture of quasi‐brittle materials such as ceramics and cement‐based materials can be described by an R‐curve, defined as fracture resistance. The R‐curve can be constructed as the envelope of the strain energy release rates (G). In this study, R‐curve is defined as an envelope of G‐curves obtained by varying the dimensions of identical specimens, while keeping the geometry and the initial flaw size constant. By approximating the G‐curve with a second‐order function of the crack length, a simple formulation of the R‐curve is derived by solving a differential equation. Three parameters are needed for the proposed R‐curve. These parameters can be obtained by testing a notched‐beam specimen and using linear elastic fracture mechanics. The proposed R‐curve simulates well the geometry dependency as well as other characteristics of the fracture response of quasi‐brittle materials.

Original languageEnglish (US)
Pages (from-to)2831-2836
Number of pages6
JournalJournal of the American Ceramic Society
Issue number11
StatePublished - Jan 1 1991


  • brittle materials
  • cements
  • cracks
  • models
  • R curve

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry


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