Low-velocity impact behaviour of biocomposite laminates reinforced by flax, basalt and hybrid fibres at various temperatures: Analytical, numerical and experimental results

In recent years, the non-biodegradable nature of synthetic composite materials has shifted the research focus on natural fibres as possible substitutes for traditional reinforcements. This paper investigates the effects of temperature variation on the impact behaviour of natural fibre laminates from an experimental, analytical, and numerical point of view. Flax, basalt, and hybrid/epoxy resin composites have been characterized through a variegated experimental campaign: from −40 °C to 80 °C. In addition to these studies, two different analytical models available in literature for synthetic materials are, here, combined and validated to reproduce the full loading–unloading trend of natural fibre composites. Since the aim of this study is the investigation of low-velocity impact behaviour as a function of the operating temperature, it is worth noting that no modifications have been made to these models, except for material parameters like Young’s and shear moduli. Subsequently, a finite element numerical investigation has been carried out, using the solver RADIOSS, with the aim of generating, in very reasonable computation times, a first numerical approximation of the experimental impact response. The obtained results show how both the presented procedures can predict well the response of these composites during an impact event. Moreover, the mixed trend observed in the hybrid configuration supports the thesis of hybridization’s importance, as a technique capable of exploiting the synergistic effects arising from the application of different types of reinforcement and reducing the drawbacks connected with the employment of a single type of fibre.