Mechanical and impact characterization of hybrid composite laminates with carbon, basalt and flax fibres

Ternary hybrids including carbon, basalt and flax fibres in an epoxy matrix have been fabricated by hand lay-up, then consolidated by vacuum bagging using two different stacking sequences. Both configurations involved the use of carbon fibres on the outside, whilst basalt and flax fibres were disposed internally either in a sandwich or in an intercalated sequence. They were subjected to tensile, flexural and interlaminar shear strength test, then to falling weight impact with three different energies, 12.8, 25.6 and 38.4 J, studying damage morphology and impact hysteresis cycles. Intercalation of basalt with flax layers proved beneficial for flexural and interlaminar strength. As regards impact performance, the differences between the two laminates were quite limited: however, the presence of a compact core of flax fibre laminate or else its intercalation with basalt fibre layers had a predominant effect on impact damage features, with intercalation increasing their complexity.