Repair of Impacted Thermoplastic Composite Laminates Using Induction Welding

Area of Science:

• Materials Science
• Aerospace Engineering
• Mechanical Engineering

Background:

• Thermoplastic composites are increasingly used in commercial aircraft.
• Limited repair techniques hinder wider adoption of these advanced materials.
• Developing effective repair methods is crucial for composite structural integrity.

Purpose of the Study:

• To evaluate induction welding as a repair technique for low-velocity impact damaged thermoplastic composites.
• To assess the mechanical performance of repaired carbon fibre/Polyetherketoneketone (CF/PEKK) and carbon fibre/Polyether ether ketone (CF/PEEK) laminates.
• To compare the effectiveness of two induction welding repair methods (RT-1 and RT-2).

Main Methods:

• Low-velocity impact tests were conducted on CF/PEKK and CF/PEEK laminates at 20 J.
• Repairs were performed using induction welding with a circular patch (RT-1) or heat and pressure (RT-2).
• Compression-after-impact and repair (CAI-R) tests were performed, with results compared to compression-after-impact (CAI) tests. Ultrasonic C-scans were used for damage analysis.

Main Results:

• CF/PEKK repaired with RT-1 showed a 13% strength increase compared to CAI; RT-2 showed a 7% increase.
• CF/PEEK repaired with RT-1 showed a 13% strength increase compared to CAI; RT-2 showed a 17% increase.
• Ultrasonic C-scans and CAI-R tests confirmed induction welding's viability for industrial repairs.

Conclusions:

• Induction welding is a viable repair technique for impact-damaged thermoplastic composites.
• The repair methods significantly improved the strength of both CF/PEKK and CF/PEEK laminates.
• Findings support the use of induction welding for aerospace and automotive applications, enhancing material lifecycle and sustainability.