Modelling off-axis ply matrix cracking in continuous fibre-reinforced polymer matrix composite laminates

Maria Kashtalyan, C. Soutis

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


The fracture process of composite laminates subjected to static or fatigue tensile loading involves sequential accumulation of intra- and interlaminar damage, in the form of transverse cracking, splitting and delamination, prior to catastrophic failure. Matrix cracking parallel to the fibres in the off-axis plies is the first damage mode observed. Since a damaged lamina within the laminate retains certain amount of its load-carrying capacity, it is important to predict accurately the stiffness properties of the laminate as a function of damage as well as progression of damage with the strain state. In this paper, theoretical modelling of matrix cracking in the off-axis plies of unbalanced symmetric composite laminates subjected to in-plane tensile loading is presented and discussed. A 2-D shear-lag analysis is used to determine ply stresses in a representative segment and the equivalent laminate concept is applied to derive expressions for Mode 1, Mode 11 and the total strain energy release rate associated with off-axis ply cracking. Dependence of the degraded stiffness properties and strain energy release rates on the crack density and ply orientation angle is examined for glass/epoxy laminates. Suitability of a mixed mode fracture criterion to predict the cracking onset strain is also discussed.

Original languageEnglish
Pages (from-to)6789-6790-6799
Number of pages11
JournalJournal of Materials Science
Issue number20
Publication statusPublished - 2006


  • stiffness degradation
  • transverse cracking
  • glass
  • damage
  • behavior
  • fracture
  • growth
  • microcracks
  • mehanisms


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