SIMPLIFIED TOPOLOGICAL TOUGHNESS MAPS AS TOOLS TO ASSESS THE PERFORMANCES RECOVERY OF HYBRIDIZED NATURAL FIBER REINFORCED COMPOSITES SUBJECTED TO ALTERNATE SALT-FOG/DRY CYCLE

The durability of natural fiber reinforced composites (NFRCs) in severe environmental conditions is a relevant concern due to their sensitivity to water absorption and related degradation phenomena. This study investigated the ability of hybridized NFRCs, combining flax and glass fibers, to recover their mechanical performance after exposure to salt-fog exposition. The composites were subjected to a humid/dry cycling process, simulating the alternating wet/dry cycles experienced in outdoor marine applications. Three-point bending tests were performed to assess the effects of aging on the composites' strength, stiffness, and toughness. The experimental results revealed that hybrid composites show superior recovery capabilities compared to full flax composites. Hybridization stabilized performance, with only a 10% residual strength reduction after the humid/dry cycle. Furthermore, a simplified toughness map was used with suitable results to effectively evaluate the performances degradation and recovery processes in hybridized NFRCs. This tool can assist to optimize the composite laminates and their durability in critical environmental conditions.