Multi-functional application of recycled carbon fibres in hybrid composites for notch sensitivity reduction and damage monitoring

Abstract

It is challenging to reuse recycled carbon fibres (rCF) alone as reinforcement material in composites for structural application due to its discontinuous and non-aligned fibre architecture. This study investigates innovative usage of rCF when hybridized with other reinforcement fibres in a hybrid composite for multi-functional application. A rCF non-woven is embedded in an E-glass fabric composite laminate to demonstrate its multi-functionality in open-hole specimens with various hole sizes under monotonic tensile loading. Instead of brittle failure, the rCF fails in a progressive manner due to the in-situ effect offered by the neighbouring glass fibre sublaminates. Following damage initiation in the rCF layer, delamination takes place along the rCF and glass fabric interfaces, enabling stress redistribution around the hole. This leads to reduced stress concentration, resulting in a notch-insensitive hybrid composite when compared to the non-hybrid glass fabric composite. By monitoring the change in electrical resistance of the rCF layer, the progressive damage events around the hole can be inferred. Regardless of the hole size, a simple damage self-sensing system can be developed to inform the damage severity of the hybrid composite. In this study, the rCF layer gives a damage tolerant notched composite and simultaneously offers damage monitoring functionality