Experimental and numerical investigation on the mechanical properties of hybrid glass/flax composite laminates.

Composite materials consist of a matrix and one or more reinforcements, combin- ing to form a material that enhances the properties of both components. This thesis focuses on long fiber-reinforced materials, which are widely used in various industrial sectors such as aerospace, automotive, energy, marine, and sports and leisure due to their high mechanical properties and reduced weight compared to traditional materials like aluminum alloys and steel. These properties make fiber-reinforced composite materials significant for sus- tainable applications, such as reducing fuel consumption in the automotive and aerospace industries and decreasing inertia and energy dissipation in wind turbines. To enhance the sustainability of these materials, research was conducted on the mechanical properties of a hybrid composite made with commercial materials. Four symmetric and balanced laminates composed of flax fiber and E-glass fiber, along with two additional plates each containing only one type of reinforcement, were manufactured. Flax fiber has emerged as a highly promising reinforcement for sustainable composite materials due to its superior mechanical properties compared to most other sustainable fibers studied to date. To further increase the sustainability of the composite, an epoxy resin containing a percentage of bio-based raw materials was used. An experimental campaign was conducted to obtain the principal mechanical properties of each plate, followed by a finite element (FE) analysis. The goal of this analysis was to identify the best material model to describe the laminates composed of a single fiber type and to determine the optimal parameters for using these material models to accurately reproduce the mechanical properties of the hybrid laminates. Finally, an evaluation of the trade-off between mechanical properties and sus- tainability was conducted to explore potential scenarios where a hybrid composite could be used instead of an exclusively E-glass fabric reinforced material.