Repeatable self-healing of composite?s fatigue delamination

This paper investigates repeatable self-healing of composite laminates to mitigate fatigue delamination where a two-step healing mechanism is employed to heal the delamination cracks in a CFRP composite: (i) close the cracked surfaces by thermally activating dispersed shape memory polymer (SMP) filaments, and (ii) heal the closed crack by melting the thermoplastic healant (PCL) dispersed in the thermoset polymer matrix and allowing it to flow into the cracked region and solidify. Repetitive self-healing is carried out on double cantilever beam (DCB) specimens using macro fiber composite (MFC) actuators bonded to the test specimens, which generate the heat required to activate the thermoplastic healants to heal the delamination in the composite. Fatigue delamination growth rates were obtained for replicate specimens to extract statistically meaningful data on fatigue life under mode-I loading after seven healing cycles, indicating substantial retardation in delamination growth rate resulting in a significant increase in fatigue life.

Automated summary

This paper investigates the repeatable self-healing of composite laminates using a two-step mechanism to repair delamination cracks in CFRP composites. The process involves thermally activating dispersed SMP filaments to close cracked surfaces, and then melting and solidifying the thermoplastic healant dispersed in the thermoset polymer matrix to heal the closed crack. The results showed a substantial increase in fatigue life due to the retardation in delamination growth rate after seven healing cycles.