Damping Behaviour and Self-Healing Performance Evaluation of Microcapsules Reinforced Epoxy Composites by Impulse Excitation Technique

Micro cracks developed in the composite structures can be repaired autonomously by incorporating microcapsules-based self-healing approach into the composites. In the current study, in order to employ self-healing composites in different structural applications, damping behaviour and self-healing performance of the composites were evaluated. CY230 epoxy and HY951 hardener were chosen as two different self-healing agents and encapsulated in polymethylmethacrylate (PMMA) shell material. Dual microcapsules reinforced carbon fibre epoxy composites were fabricated by employing 15wt% of microcapsules at 1:1 weight ratio and 0.5:0.5 weight fractions of matrix reinforcement. Influence of microcapsules addition and induced damages on the damping behaviour and self-healing performance of the pure epoxy and pure carbon fibre reinforced polymer (CFRP) composites were investigated by impulse excitation technique (IET). It was noticed that with the addition of respective optimized 7.5 wt%, 15 wt% microcapsules to pure epoxy and pure CFRP, damping factor of both the composites increased whereas elastic modulus decreased. Compared to capsules reinforced virgin composites, damping factor of damaged composites was higher in both types of composites. Self-healing efficiency of capsules reinforced pure epoxy and carbon fibre epoxy composites were calculated based on the recovery in stiffness of the composites and noticed respective healing efficiencies of 72.05% and 53.72% at optimized healing conditions and microcapsules concentration.