Efficient joints for high-performance composite aerostructures Composite aircraft structures are joined together with a variety of techniques and materials. EU-funded scientists introduced new solutions for fastener reinforcement for lighter aircraft and cost-effective assembly and maintenance. Health © Alex_Schmidt, Thinkstock The widespread use of carbon fibre-reinforced plastics (CFRPs) in the aerospace industry has enabled significant savings in weight and associated fuel consumption and emissions. Despite inherently superior mechanical properties in terms of stiffness-to-weight ratio, for full exploitation of CFRPs more efficient joining systems are needed to ensure damage-tolerant structures. Critical components in aircraft, such as the fuselage and wings, have several interfaces that require safe transfer of loads between composite parts with reduced weight and cost. This is necessary to increase the competitive position of the EU aircraft industry. Within the EU-funded project CERFAC (Cost effective reinforcement of fastener areas in composites), scientists delivered advanced reinforcement solutions for use in primary composite aircraft structures. The innovative and efficient joining concepts combine several reinforcement solutions to further reduce the number of fasteners, while increasing the load-bearing capacity and damage tolerance of the assembly. This also represents a significant step towards reduced manufacturing cost. Working with the latest composite materials based on carbon, scientists targeted three applications. These included generic butt straps for assembling thin-walled structures, advanced joints for final assembly of fuselage shells or barrels, and thicker laminates or thickened zones of thin-walled parts for more efficient and safer transfer of concentrated loads. The new types of lighter and cheaper joints increase the strength-to-cost ratio and damage tolerance of fastener areas. CERFAC's advanced reinforcement solutions for aircraft composite structures enhance the performance while reducing the number of fasteners required. This enables cost-effective manufacturing and assembly solutions through substantial reductions in weight, fuel consumption and emissions. As a result, the manufacturing, assembly, and inspection and maintenance costs of the aircraft industry can be reduced considerably. Keywords Joints, composite, aircraft structures, fastener, CERFAC
