On-surface fibre-free zones and irregularity of piercing pattern in structurally stitched NCF preforms

V. Koysin, Andreas Ruopp, Stepan V. Lomov, Ignaas Verpoest, Volker Witzel, Klaus Drechsler

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The paper addresses the surface imperfections (openings in fibrous plies) and irregularity of the piercing pattern in structurally stitched multilayer carbon-fibre preforms. Each layer is a multiaxial multiply non-crimp fabric (NCF) with a non-structural stitching. The term “structural” presumes here that the stitching yarn does not only consolidate the plies (as the non-structural one does) but forms also a through-the-thickness (3D) reinforcement. Four stitching methods are studied: ordinary CNC-sewing, tufting, dual-needle, and curved needle techniques with multifilament yarns: aramide (60 or 120 tex) or glass (204 tex). In total, 14 stitching cases are investigated experimentally. It is observed that a non-negligible variability exists in the meso-level geometry of the reinforcement. The geometrical characterization provides important input data for analysis of the permeability and mechanical properties of the preforms.
Original languageUndefined
Pages (from-to)81-88
JournalAdvanced Composites Letters
Issue number3
Publication statusPublished - 2006


  • IR-75506
  • NCF
  • Textile Composite
  • quality analysis
  • Structural Stitching
  • geometrical characterisation

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