Analysis of the tensile behaviour of hybrid recycled carbon fibre composites performed using digital image correlation technique

The increasing demand for sustainable materials has driven the development of hybrid composites to improve mechanical properties while reducing environmental impact. This study investigates the notch insensitivity and strain distribution behaviour of three hybrid composites: carbon fibre/recycled carbon fibre (CF/rCF), glass fibre/recycled carbon fibre (GF/rCF), and flax fibre/recycled carbon fibre (FF/rCF). Digital Image Correlation (DIC) analysis was employed to examine strain distribution and crack initiation across different loading conditions for both hybrid and non-hybrid composites. Results indicate that the CF/rCF and GF/rCF hybrids improved notch insensitivity and resistance to crack propagation compared to pure CF and GF composites, with rCF contributing to stress distribution and delaying crack initiation. Conversely, the FF/rCF hybrid displayed higher strain concentrations around notches than pure flax fibre, suggesting that hybridization with rCF may not provide the same benefits for natural fibres. These findings highlight the potential of hybrid composites for applications that require both durability, sustainability, and underscore the influence of fibre type on the effectiveness of hybridization. This research advances our understanding of the mechanical performance of sustainable hybrid composites and provides a foundation for the development of optimized materials for eco-friendly applications. These materials show promise for use in automotive, marine, and secondary aerospace structures where sustainable, damage-tolerant composites are needed.