Injection repair for advanced aerospace composite materials

Advanced composites have been widely adopted as a material of choice within the aerospace industry for more than 40 years, owing to their exceptional quality, low density, and high stiffness and strength. However, their complex nature of damage continues to pose challenges for structural repairs. Since damage is inevitable in any structure, a reliable and efficient repair technique is essential to support the ongoing use of composites across various industries and applications. A viable repair method should account for the limitations of available equipment and resources, as well as the preservation of repair materials, particularly for rapid repairs with minimal aircraft downtime. This paper reviews the application of resin injection for repairing aircraft composite structures as a non-invasive and cost-effective alternative to existing repair methods. The primary focus of this review is on the resin’s ability to infiltrate the damaged area, as this directly influences the rate of strength recovery. Many researchers have assessed the injection method’s tolerance and strength restoration capacity while suggesting or recommending certain processes. However, achieving complete penetration remains challenging, especially for more complex damage caused by impact.