Demonstration of pseudo-ductility in all fibre directions of high performance quasi-isotropic thin ply carbon/glass hybrid composites

Hybridisation is one of the approaches to introduce pseudo-ductility to brittle composite materials. In this approach, two or more different types of fibre are combined and if the configuration and material constituents are well selected, the tensile response shows a gradual failure and a metal-like stress-strain curve with a pseudo-yield point. Different types of unidirectional and quasi-isotropic (QI) hybrid composites with continuous layers have been studied to produce pseudo-ductile tensile behaviour in one loading orientation when subjected to tension. However, most composite structures are subjected to multiple loading orientations, therefore, the aim of this paper is to exploit the potential of thin-ply carbon/glass hybrid laminates with dispersed orientations to generate high performance QI composite plates that show pseudo-ductility in all the fibre orientations under tensile loading. QI sublaminates were used to fabricate novel architectures made up of a QI Skyflex thin ply high strength T300-carbon/120°C epoxy sub-laminates sandwiched between the two QI Hexcel standard thickness S-glass/913 epoxy sub-laminates. The results show that by choosing an appropriate ratio of the carbon thickness to the laminate thickness and material properties, a desirable pseudo-ductile failure can be achieved in all the fibre orientations.