Impact damage resistance of novel adhesively bonded natural fibre composite – Steel hybrid laminates

Synthetic fibre reinforcements are increasingly replaced with plant fibres but an improvement in the mechanical performance of biocomposites is required. Flax composite exhibits fibre failure and perforation even at low impact energies. This paper investigates the viability of improving the impact resistance of flax-epoxy biocomposite by hybridisation with a thin metal layer. High-speed cameras and optical microscopy were used to measure the dissipated energy and to identify the different damage modes. The impact response of hybrid biocomposites was compared to a reference GFRP composite and monolithic biocomposites and it was shown that the deformation and damage is significantly reduced in the hybrid configuration. Additionally, a numerical model was developed in Abaqus/Explicit and validated in terms of the displacement history and damage modes. The study reveals the effect of various material configurations and thicknesses on impact damage resistance and proves that the penetration resistance of biocomposites is improved by hybrid construction.