Computational analysis of the mechanical behaviour of flake-based recycled composites

This study presents a computational framework for evaluating the mechanical behaviour of flake-based recycled composites. Three-dimensional representative volume elements (RVEs) are constructed to estimate effective elastic properties and capture local stress distributions. The influence of meso-structural features, such as out-of-plane flake orientation, flake length, and resin-rich regions, on RVE size and representativeness is systematically investigated to ensure accurate and reliable predictions. Furthermore, the effect of flake length on both local and global mechanical responses is examined in detail. The results demonstrate that the composite’s effective properties are governed by flake length: the in-plane elastic moduli increase with longer flakes, whereas the out-of-plane properties remain largely unchanged. Locally, longer flakes develop more uniform longitudinal and out-of-plane stresses, while the in-plane and resin stresses tend to increase. The approach opens a pathway towards design and optimisation of recycled composites, supporting the development of high-value, circular composite systems.