Interlaminar toughness of interleaved CFRP using non-woven veils: Part 1. Mode-I testing

The objective of this research is to investigate the interlaminar toughness of CFRP by non-woven interleaf veils. Test samples were fabricated by the vacuum assisted resin transfer moulding (VaRTM) technique. Some interleaf materials may be restricted for use in VaRTM because resin flow would be prevented in the through-thickness direction. However non-woven veils can be used with a VaRTM technique. A series of carbon fibre laminates based on woven fabrics and unidirectional plies were manufactured with a variety of different inter-ply, non-woven veils. The veils were produced from thermoplastic fibres, carbon fibres and combinations of the two, and tested for Mode-I interlaminar toughness. Composites produced with polyester veil in the inter-ply region exhibited significant improvements in Mode-I interlaminar toughness. In contrast, carbon veil interleaved laminates had the poorest Mode-I interlaminar toughness. Fibre-bridging effects by the interleaf veil fibres contributed significantly to the toughening mechanism in Mode-I loading.