Influence of nonwoven interleave layer on interlaminar fracture of sandwich-structured composites

Authors

  • Zain Ali Department of Textile Technologies, Chemnitz University of Technology
  • Jakob Schmidt Department of Textile Technologies, Chemnitz University of Technology
  • Jörg Kaufmann Department of Textile Technologies, Chemnitz University of Technology
  • Holger Cebulla Department of Textile Technologies, Chemnitz University of Technology

DOI:

https://doi.org/10.21935/tls.v5i1.153

Abstract

Debonding between the skins and the core is one of the critical failure modes encountered by sandwich-structured composites in highly strained conditions. The onset and growth of a debond critically hinder the load-bearing capacity of the sandwich structure. This paper investigates the effect on the debonding resistance of a sandwich-structured composite by the addition of nonwoven flax interleave veil in the skin-core interface. Mode-II fracture toughness is estimated through a proposed method based on curve fitting of numerical data to experimental results. Experimental data are obtained in a four-point bending test following the standard DIN 53 293 and Cohesive Zone Modelling (CZM) is implemented as the numerical tool in the analysis of Mode-II skin-core debonding. A series of sandwich specimens are fabricated using twill weave e-glass fabric and expanded polystyrene core with and without the addition of an interleave layer. Numerical data show a 60 % increment in Mode-II fracture toughness with the inclusion of a flax interleaf layer. Microscopic images attribute the increment to the presence of fibre bridging effect. The proposed method produces a good fit of numerical data to experimental results.

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Published

2022-03-28