Pseudo-ductile unidirectional high modulus/high strength carbon fibre hybrids using conventional ply thickness prepregs

摘要

Pseudo-ductile hybrid composites usually require thin plies. In contrast, in the present paper unidirectional fibre-hybrid composites with conventional ply thicknesses are investigated. A prepreg with DIALEAD fibres and a 0.22 mm thickness was used as the high-modulus/low-elongation (LE) layer, combined with a prepreg with T800 fibres and a 0.11 mm thickness as the intermediate modulus/high-elongation (HE) layer. For hybrids with an LE volume fraction of 33% and below, pseudo-ductile behaviour in tension was obtained. The hybrid with an LE volume fraction of 50% has shown a transitional behaviour, mixing pseudo-ductility with a sharp stress drop after the failure of LE layer. The fracture mechanisms were interpreted using edge optical observation, full-field registration of the surface strain maps and analysis of the amplitude and frequency of acoustic emission signals. The pseudo-ductility was caused by the stable, progressive delamination of the LE/HE interface.