Falling-weight impact and post-impact flexural performance of hybrid flax/carbon laminates

Hybrid laminates produced using carbon (C) and flax (F) fiber pre-pregs with epoxy resin were fabricated, with two different stacking sequences, in general terms based on the presence of flax fiber laminates as outer layers and carbon as inner layers (FCF) or vice versa. Pure flax and pure carbon fiber reinforced laminates were also fabricated for comparison. Experimental tests were performed, which included four-point bending, falling weight impact tests at energies ranging from 5 to 30 Joules with determination of the BVID and post-impact flexural tests. In general terms, CFC proved slightly superior to FCF as for flexural performance, although on the other side the presence of flax laminates on the outside guaranteed a higher impact damage tolerance, acting as hindrances to crack propagation in the laminate.