Review of Adhesive Bonding in Aircraft Structures: Advances, Challenges and Future Trends

Abstract

Adhesive bonding has emerged as a crucial joining method in the aerospace industry, offering advantages such as weight reduction, improved fatigue resistance, and enhanced corrosion resistance. Recent advances in adhesive materials, bonding processes, and quality-assurance techniques have further expanded the potential of adhesive bonding in aircraft structures. High-performance structural adhesives, including toughened epoxies, bismaleimide, and cyanate ester adhesives, have been developed to address extreme operating conditions. Multifunctional and smart adhesives that incorporate nanomaterials and self-healing capabilities are being explored to improve bonded-joint performance and durability. Advances in surface preparation, such as laser ablation, atmospheric pressure plasma treatment, and sol-gel processes, have improved bonding reliability. Out-of-autoclave processing and advanced curing methods have increased efficiency and reduced manufacturing costs. Extended non-destructive testing techniques, including phased array ultrasonic testing, active thermography, and terahertz imaging, enable more effective evaluation of bonding quality. However, challenges remain, including moisture ingress, thermal cycling, and the detection of kissing bonds. Future trends include self-healing and damage-tolerant adhesives, sustainable and recyclable bonding systems, and the integration of digital twin technology for process optimisation and quality control. The shift from post-process NDT to integrated structural health monitoring systems, together with AI-powered data analysis is expected to revolutionise the certification and maintenance of bonded aerospace structures.