Improving the mechanical properties of natural fibre reinforced laminates composites through Biomimicry

•Helicoidal configuration reduces and delays natural fibre damage in NFRP laminate.•Stacking NFRP laminate helicoidally significantly improves its loading performance.•The large matrix damage in helicoidal NFRP laminate dissipates more impact energy. Although they have lower stiffness and load bearing capabilities than composites reinforced with synthetic fibers, there is increasing attention on natural fiber reinforced plastic (NFRP) laminates because of their environmental sustainability. Instead of focusing on the mechanical properties of natural fibers, this study demonstrates that the mechanical performance of NFRP laminates can be improved by adopting a helicoidal laminate stacking configuration that is found in the exoskeletons of crustaceans. Helicoidal NFRP laminates with different inter-ply angles were fabricated from flax-epoxy prepreg and tested under out-of-plane and impact loads. The results show that a helicoidal configuration with 9° inter-ply angle improved the peak load of the NFRP laminate by 72% and 52% respectively when compared against the common cross-ply and quasi-isotropic configurations. Helicoidal NFRP laminates are also shown to absorb more energy under impact as compared to the cross-ply and quasi-isotropic NFRP laminates.