Interlaminar and translaminar fracture toughness of Automated Manufactured Bio-inspired CFRP laminates
Verónica Rodríguez, M. Herráez, Vanesa Baños Martínez, Roberto Guzmán de Villoria
Abstract
Natural structures such as nacre show an outstanding balance of strength and toughness, despite comprising mainly brittle constituents; this is a highly desirable combination of properties scarcely seen in synthetic composites. In this study, carbon fibre-reinforced polymer (CFRP) laminates mimicking the structure of nacre (‘brick-and-mortar’) were manufactured using the automated tape laying (ATL) technique, as a means of enhancing their interlaminar properties and fracture toughness. The interlaminar fracture toughness of the bio-inspired CFRP laminates was measured via double cantilever beam (DCB) and three-point bending end-notched flexure (3ENF) tests. The results indicated increments of up to 32% and 92%, respectively, in the interlaminar fracture toughness when compared with that of conventional continuous CFRP samples. In addition, the translaminar fracture toughness of the developed nacre-inspired CFRPs was measured through a compact tension (CT) test, which revealed increments of up to 30%. Finally, different reinforcement mechanisms were analysed to understand the effect of the ‘brick-and-mortar’ structure.