Comparing the impact resistance of flax/epoxy and glass/epoxy composites through experiments and numerical simulations

Natural fibers are fostered to replace traditional fibers in long-fiber composites due to their reduced environmental impact. While carbon fibers compete on a league on their own, natural fibers are foreseen to be a viable alternative to glass fibers due to a similar specific strength under certain loading conditions. The purpose of this paper is to compare the impact resistance of natural fiber composites against a similar glass-fiber counterpart. This work presents an experimental study investigating low-velocity impacts on stress-free flax-and glass-based laminates sharing the same matrix system, have similar quasi-isotropic lamination sequences, and have been designed to be similar in weight. Such an approach further leads to laminates with similar flexural modulus, allowing for a direct comparison of the impact resistance. Insights on the major damage mechanism and the damage evolution during the impact are further gained through numerical simulations. Results show that the impact resistance of natural fiber composites is drastically lower than their glass counterparts, and such behavior should be mainly ascribed to the lower fiber strength. Further, the proposed numerical model gives insight on modeling parameters that can be utilized to improve the reliability of the numerical solution in terms of energy absorption during the impact.