Evaluating the effectiveness of fusion bond repairs on impact damaged thermoplastic composites

Abstract Adhesive bonded repairs are commonly used to restore the strength of impact‐damaged thermoset composites. However, due to low surface energy, thermoplastic composites face bonding challenges. Fusion bonding bypasses this issue by re‐welding delamination cracks in damaged thermoplastic composites. This paper investigates the effectiveness of fusion bond repairs on impact‐damaged thermoplastic composites without applying a reinforcing patch. The residual compressive strength was assessed at various impact energies to quantitatively assess the damage severity and strength recovery. The methodology includes inducing low‐velocity impacts on carbon fiber/polyether‐ether‐ketone (CF/PEEK) laminates, followed by fusion bond repair using heat and pressure. Non‐destructive evaluation techniques like ultrasonic C‐scan and x‐ray computed tomography were used to characterize damage and evaluate repair effectiveness. Results showed good recovery of residual compressive strength, highlighting the feasibility of fusion bond repairs for thermoplastic composites and their potential application in aerospace and other industries. Highlights Carbon fiber/polyether‐ether‐ketone composite laminates were subjected to three impact energies and non‐destructive evaluation confirmed varying levels of damage severity. The damaged specimens were healed using the fusion bond technique without removal of the damaged area or adhesive bonding of repair patches. The delaminations were completely healed, and the specimens showed full recovery in residual compressive strength.