Determination of fracture toughness by photoelastic coating

H. C. Soo*, Isaac M Daniel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The photoelastic-coating method was applied to the determination of fracture toughness in aluminum plates. The specimens were plates with a central transverse crack. Determinations were made first by the compliance method. The specimens were loaded statically to failure. The opening displacement across the crack was measured with a clip gage. In using this photoelastic-coating method, the stress-intensity factor was obtained in terms of the radius and fringe order of various isochromatic fringe loops using an extrapolation law. An apparent stress-intensity factor was obtained from several isochromatic fringe patterns away from the crack tip and then extrapolated to the crack tip to determine the true value. Results obtained by the photoelastic-coating method are higher than those obtained by the compliance method for all loads, due to the bluntness of the crack tip in the first set of specimens. Theoretical predictions fall between the compliance method and photoelastic-coating results.

Original languageEnglish (US)
Pages (from-to)10-13
Number of pages4
JournalExperimental Mechanics
Issue number1
StatePublished - Mar 1 1987

ASJC Scopus subject areas

  • Mechanics of Materials
  • Computational Mechanics


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