Hybridization of Thin Laminates with Natural Fibers: A Comparison Study Between Hemp and Flax

In recent years, the rapid growth of interest in the use of natural fibers (NFs) as reinforcement for composites, due to their reduced environmental impact and low-cost, generated several research studies aimed at the study of manufacturing processes of natural fibers polymeric composites and their innovative applications. However, composite reinforced by natural fibers like hemp or flax are currently mainly used for non-structural applications because of their high variability in mechanical properties, lower mechanical performances if compared to synthetic fibers and susceptibility to humidity. Consequently, a possible method for overcoming these problems and expanding NF applications also for structural components, could be their use in hybrid systems. In particular, the development of hybrid panels characterized by a combination of two different reinforcements, guarantees higher tailorability of the structure, alleviating the inherent drawbacks of each of the different fibers while keeping the benefits of both, and at the same time enables synergistic effects that can lead to properties that neither of the constituents possesses, leading to the extension of the application fields for some materials that alone do not possess the required properties. Therefore, this paper is focused on the study of the production and mechanical characterization in terms of impact performances of hybrid thin sandwich panels consisting in CFRP skins and a thin hemp and flax bigrid as core that was manufactured with an ad hoc continuous manufacturing process.