Self-healing of matrix cracking and delamination damage assessment in microcapsules reinforced carbon fibre epoxy composite under flexural loading

Structural integrity of micro cracked CFRP composite structures can be re-established by incorporating the microcapsules based self-healing system into the composite. In the current study, in order to fabricate capsules reinforced CFRP composite, 0.54: 0.39: 0.07 vol fractions of matrix, carbon fibre and separately encapsulated epoxy, hardener microcapsules were employed. Effect of microcapsules addition and induced damage on the flexural strength of the composite were investigated. It was noticed that flexural strength decreases with the increase in capsules concentration and for 5 wt% capsules reinforced composite flexural strength reduced by 21.73%, 29.32% due to induce of matrix cracking and delamination damage respectively. In order to assess self healing performance of the composite, different damage events were induced in the composite and healing efficiency was evaluated based on the recovery in flexural strength. Effect of capsules wt%, healing temperature and pressure on the healing efficiency were assessed and noticed higher healing efficiencies at elevated temperature and pressure healing conditions. Healing efficiencies of 71.30%, 54.21% were obtained at optimal healing conditions for matrix cracking, delamination damage recovery respectively. Crack path deflection, crack pinning and capsules rupture mechanisms were observed in the microstructural investigation of fracture surface of capsule reinforced composite.

Automated summary

The structural integrity of micro-cracked CFRP composite structures can be re-established by incorporating a self-healing system based on microcapsules. The addition of microcapsules reduces the flexural strength of the composite, but the healing efficiency can be improved by adjusting the concentration of capsules, healing temperature, and pressure. Microstructural investigation reveals crack path deflection, crack pinning, and capsules rupture mechanisms in the fracture surface of the capsule-reinforced composite.