Fracture toughness of three-dimensional stereolithography printed polymer reinforced with continuous carbon fibres

Additive manufacturing of fibre-reinforced polymers is one of the latest technical developments in composites manufacturing. However, there is a severe shortage of research into continuous fibre-reinforced polymers manufactured through stereolithography. For the first time, this paper investigates the fracture properties of continuous carbon fibre-reinforced polymer produced by 3D stereolithography printing. Compact tension specimens, both plain and fibre reinforced, were produced and tested systematically. The results showed a significant improvement in fracture toughness for fibre-reinforced specimens when compared to plain ones. The positioning of fibre bundles had a substantial effect on fracture properties, and a higher fracture toughness was reported for specimens with the fibre bundle placed closer to the crack tip. By increasing the number of fibre bundles, a significant increase in fracture toughness was reported when compared to the sample with a single fibre bundle, indicating a strong contribution of fibre volume. Also, the contribution appeared to be most effective when the fibre bundles were placed symmetrically in the thickness direction. The work is of importance and value for the development of the stereolithography technique in manufacturing continuous fibre-reinforced composites with enhanced mechanical properties.