Thermosetting Composite Materials in Aerostructures

Abstract

Thermosetting composites in aircraft structures are typically based on high-performance reinforcing materials, such as carbon fibre, held together by polymer resins, such as epoxies, which undergo an irreversible curing reaction to form the desired structural components. Compared to conventional metallic materials used in aerostructures, thermosetting composites offer superior specific strength and stiffness, along with improved corrosion and fatigue resistance. This can lead to significant gains in performance and fuel efficiency, along with reduced maintenance requirements. Consequently, these materials continue to gain favour in aircraft construction. The drive towards lower production costs, partly facilitated through the development of larger integrated structural components at higher production rates, is leading to new innovations in manufacturing. Advances in liquid resin infusion methodologies are helping to produce such large structural components more economically, while the development of automated fibre placement technologies is enhancing production quality and minimising conventional labour costs. However, a lack of maturity and experience in the analysis, design, manufacture, and maintenance of composite aerostructures continue to necessitate the need for greater research. For example, improvements in non-destructive inspection and adhesively bonded repairs are required to make composite maintenance more efficient and reliable. Further weight savings and performance benefits could also be achieved by integrating essential systems within composite structures, imbuing them with ‘multifunctionality’. Composite waste is another significant issue, given the projected increase in demand for these materials. In particular, thermoset composite recycling is expected to be a key technology requirement.