A novel model of delamination bridging via Z-pins in composite laminates

G. Allegri*, M. Yasaee, I. K. Partridge, S. R. Hallett

*Corresponding author for this work

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

35 Citations (Scopus)
294 Downloads (Pure)

Abstract

A new micro-mechanical model is proposed for describing the bridging actions exerted by throughthickness reinforcement on delaminations in prepreg based composite materials, subjected to a mixedmode (I-II) loading regime. The model applies to micro-fasteners in the form of brittle fibrous rods (Z-pins) inserted in the through-thickness direction of composite laminates. These are described as Euler-Bernoulli beams inserted in an elastic foundation that represents the embedding composite laminate. Equilibrium equations that relate the delamination opening/sliding displacements to the bridging forces exerted by the Z-pins on the interlaminar crack edges are derived. The Z-pin failure meso-mechanics is explained in terms of the laminate architecture and the delamination mode. The apparent fracture toughness of Z-pinned laminates is obtained from as energy dissipated by the pull out of the throughthickness reinforcement, normalised with respect to a reference area. The model is validated by means of experimental data obtained for single carbon/BMI Z-pins inserted in a quasi-isotropic laminate. (C) 2014 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)3314-3332
Number of pages19
JournalInternational Journal of Solids and Structures
Volume51
Issue number19-20
DOIs
Publication statusPublished - 1 Oct 2014

Structured keywords

  • Composites UTC

Keywords

  • Composite materials
  • Fibre reinforced
  • Delamination
  • Toughness
  • CARBON-FIBER-EPOXY
  • T-JOINTS
  • MECHANISMS
  • TOUGHNESS
  • FRACTURE
  • PERFORMANCE
  • STRENGTH
  • TENSION
  • CRACKS

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