Low-velocity impact damage characteristics of flax/glass epoxy hybrid laminates on the influence of different temperatures: Experimental and numerical analysis

This study investigated the effects of different temperatures on the low-velocity impact damage behaviour of flax fibre-reinforced epoxy composites and their glass/flax hybrids. Composites reinforced with flax, glass, and hybrid flax/glass onto epoxy matrix Subjected to low-velocity drop weight impact tests at 5 J of incident impact energy at sub-zero temperatures (−10 °C and −20 °C) and at room temperature (RT) are presented. Under the different temperatures, the experimental findings showed a beneficial hybrid effect where the temperature played a significant role. At RT, the Lam-GFGFGFG exhibit improved impact resistance, with enhanced energy absorption capabilities compared to glass-only laminates (Lam-G). Besides, Lam-GFFFFG laminates exhibit a significant difference in the force–displacement curves at − 20 °C, with a maximum load of 801.95 N in contrast to RT and − 10 °C resulting in a gradual increase in force with increasing displacement. This indicates that Lam-GFFFFG laminates can resist the impact and maintain structural integrity at sub-zero temperatures. The alternation of glass and flax layers in the hybrid structure contributes to the synergistic effects, resulting in improved damage resistance and tolerance. Also, the highest impact tolerance in a laminate is achieved through the hybridisation of flax fibre-reinforced composites with glass-reinforced layers on the outer surfaces (Lam-GFFFFG) at − 10 °C. Subsequently, experimental results were compared with finite element analysis (FEA) results, derived from a model built using a VUMAT subroutine integrated with ABAQUS/Explicit for a more accurate representation of the damage characterisation of the composite laminates under low-velocity impact.