Numerical analysis of resin-rich areas and their effects on failure initiation of composites

Hossein Ghayoor*, Catharine C. Marsden, Suong V. Hoa, António R. Melro

*Corresponding author for this work

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

23 Citations (Scopus)
192 Downloads (Pure)


Resin-rich areas in composite laminates can occur as inter-laminar resin ‘layers’ between plies or as intra-laminar resin ‘pockets’ within a single layer. In this work, numerical methods are used to study the effects of resin pockets on the transverse stiffness and failure initiation of carbon-epoxy composites. Random, or non-uniform, representative volume elements (RVE) with and without embedded resin pockets were studied. Three different types of samples with predefined volume fractions (Vf) were analyzed, and data relating to the influence of resin pockets on homogenized stiffness and the strain at which failure initiates was collected and reported. Based on a control sample for each volume fraction, two methods were used to create RVE samples with resin pockets. In one, the distances between fibers were maintained and fibers removed to create the resin pocket, with a corresponding decrease in (Vf). In the second method, the Vf was maintained and fibers were moved to create the resin pocket, with a corresponding reduction in the distance between fibers. It is shown that intra-laminar resin pockets can reduce both the stiffness and the failure strain of composite materials. Stiffness was reduced in samples where the resin pocket resulted in a reduced volume fraction. For samples with the same volume fraction, particularly for high Vf composites (e.g. 60%), the failure initiation strain in the matrix was, on average, 20% lower for samples with resin pockets compared to samples without resin pockets.

Original languageEnglish
Pages (from-to)125-133
Number of pages9
JournalComposites Part A: Applied Science and Manufacturing
Early online date17 Nov 2018
Publication statusPublished - Feb 2019


  • Resin-rich areas
  • Micromechanics
  • Representative volume element (RVE)
  • Finite element
  • Defects
  • Failure initiation


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