Effect of hybrid yarn structure on the delamination behaviour of thermoplastic composites

Continuous-glass-fibre-reinforced polyamide-matrix composites have been manufactured on the basis of hybrid yarns with different arrangements of the reinforcing glass and polyamide matrix fibres. In addition, glass fibres with different sizings were used. To characterize the delamination behaviour of composites made with these semifinished products, mechanical and fracture mechanical tests were performed, including longitudinal and transverse tensile, compression shear, double cantilever beam, single-edge notched and end-notched flexure tests. The results demonstrate the significant influence of the different hybrid yam structures and glass fibre coatings on fracture toughness. The best mechanical and fracture mechanical properties have been obtained for composites manufactured with air-textured commingled yams containing glass fibres only with aminosilane as coupling agent. (C) 1998 Published by Elsevier Science Ltd.,All rights reserved.