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Special Issue on Primary Bonded Repairs in Composite Structures

In recent years, there has been a significant increase in the usage of advanced polymer composites in the design of engineering structures – especially for primary load carrying structural members. For example, to combat the environmental threat that aviation industry poses, the aerospace industry has been aiming to considerably reduce emissions through weight reduction, aerodynamic improvements, and new aircraft concepts. For significant weight reduction, the application of composite materials in aircraft design is globally considered as one of the key technologies to meet emission targets. Advanced composite materials have replaced traditional structural materials in new generation civil aircraft structures to a significant extent (e.g., Boeing 787, Airbus A350, and Bombardier CSeries, with approximately 50% composites by weight). In addition to the improvements in fuel-efficiency and emission reduction due to lightweight designs, composite aircraft also improve passenger comfort by allowing more comfortable levels of cabin pressure and humidity. Similarly, the global wind energy industry has in recent years seen a significant growth through on-shore and off-shore wind farms – with individual turbine capacity ranging from 1 to 7MW (e.g., Vestas V90 3MW, Gamesa G128 4.5MW, and Enercon E126 7.5MW) and the development of larger turbines with 8–10MW for off-shore installation. With increasing installations and growing turbine sizes, advanced composites play a key role in the design of wind turbine blades. However, while composites are currently being used in both secondary and primary structural components, the safety, efficiency, and service life of composite structures will depend on structural maintenance and repair techniques. Moreover, as recycling thermoset-based composite materials is a major challenge, extending the service life of damaged composite components made of thermoset polymers is very important. While composite research and development activities are in progress worldwide, robust technologies for repairing primary composite structures is absolutely essential for the industry at this important juncture. The focus of this special issue of The Journal of Adhesion is on primary bonded repair of composite structures. This issue contains five invited papers on the aspects of primary composite bonded repairs. The first paper presents the challenges involved in the certification of primary bonded aircraft repairs. Although application of reinforcements attached to the parent structure by adhesive bonding is generally the The Journal of Adhesion, 91:1–3, 2015 Copyright # Taylor & Francis Group, LLC ISSN: 0021-8464 print=1545-5823 online DOI: 10.1080/00218464.2014.916105