Mechanical performance of Arundo donax engineered panels: experimental and numerical approaches

The thesis explores the mechanical performance of panels made with Arundo donax (AD), a perennial herbaceous plant widely distributed in Italy. The research focused on the production and characterisation of three types of panels: 1. Honeycomb panels: These panels were designed with a core made of AD rings and skins of flax fibre reinforced with epoxy resin. Experimental tests, including three-point bending and pull-off tests, were conducted to evaluate the adhesion between the core and the skins. It was observed that roughening the outer surface of the AD rings significantly improves shear and bending mechanical properties. Additionally, a finite element model (FEM) was developed to predict the mechanical behaviour of the panels. 2. Sandwich particleboards: Produced in collaboration with Gruppo Saviola, these panels use a core made of recycled wood chips and AD particles. This project aimed to demonstrate that substituting recycled wood with AD can enhance the physical and mechanical performance of the panels. This material allowed the transition from non-structural to structural performing panels without increasing the resin content. 3. Binderless panels: Developed in collaboration with the start-up My.Fibres, these panels incorporate various aggregates, including AD and use pre-treated hemp fibres (Mytrill) as the matrix, through an innovative process. It was observed that the physical and mechanical properties of the material are independent of the type and nature of the aggregate used, while these properties improve with higher density and increased Mytrill content relative to the aggregate. This innovative approach aims to produce fully natural panels. The primary objective of the doctoral research was to demonstrate the feasibility and benefits both in terms of performance and the environmental impact of using natural materials as an alternative to traditional construction materials, thereby contributing to the green transition in the construction sector.