Measurement of crack opening displacement and energy release rate of rapidly bifurcating cracks in PMMA by high-speed holographic microscopy

Shinichi Suzuki, Kenichi Sakaue

Research output: Contribution to journalArticle

5 Citations (Scopus)


High-speed holographic microscopy is applied to take three successive photographs of fast propagating cracks at the moment of bifurcation. The cracks are propagated in PMMA plate specimens at a speed about 660 m/s. From the photographs, crack opening displacement (COD) is measured along the cracks as a function of distance r from the crack tips. The measurement results show that the CODs are proportional to √r before bifurcation. After bifurcation, the CODs of mother cracks are proportional to √r, however, the CODs of branch cracks are not always proportional to √r. Crack speed is also measured from the photographs. As a result, discontinuous change of crack speed is not observed at the moment of bifurcation. The energy release rate and energy flux toward crack tips are obtained from the COD data, and are found to be continuous across the bifurcation point. The energy release rate and energy flux increase gradually across the bifurcation point.

Original languageEnglish
Pages (from-to)264-273
Number of pages10
JournalJSME International Journal, Series A: Solid Mechanics and Material Engineering
Issue number3
Publication statusPublished - 2004 Jul 1



  • Brittle fracture
  • Crack bifurcation
  • Crack opening displacement
  • Energy Release rate
  • Fracture mechanics
  • Holography
  • Microscopy
  • Optical measurement
  • Speed photography

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanical Engineering

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