The Effect of Fibre Bridging on Mode I Interlaminar Fracture Toughness of Carbon-Aramid/Epoxy Intra-Ply Hybrid Laminates

The present study investigates mode I interlaminar fracture toughness of aramid/epoxy, carbon/epoxy and intra-ply hybrid composites, obtained from carbon and aramid fibres as the reinforcement of an epoxy matrix, maintaining the total fibre content equal to 50 wt.%. The bidirectional, woven fabric specimens were fabricated using vacuum moulding technique. Double Cantilever Beam (DCB) test configuration was used to study the Mode I interlaminar fracture toughness. Two not very different pre-crack lengths were considered for the present study, namely 40 and 42 mm, to show the influence of small variations on crack development during fracture. The obtained results are compared according to their energy release rate GIC: this indicates that the intra-ply composition shows enhanced delamination resistance with respect to the other two materials. The results also show that the intra-ply hybrid composite has the highest fracture toughness. The maximum critical load and corresponding deflection are closely related in experimental results and theoretical prediction.