A new era for aircraft composites

Thermoset plastics (those that are heated and formed once and then cannot be reused) have dominated the field. They are easier to process and have better performance at high temperatures compared to thermoplastic polymers that can be melted and reused. In addition, much more research and experience has been accumulated regarding processing and use.

The EU-funded project 'Eco-design and manufacturing of thermoplastic structural fairings for helicopters' (ECO-FAIRS) exploited recent advances in thermoplastics materials and processing for eco-friendly aircraft structural components. Scientists took advantage of their promising hot/wet mechanical properties, durability, short production cycles and joining efficiencies that support reduced tooling and production costs.

ECO-FAIRS developed a robust methodology for design and manufacture of thermoplastic composite structural components for the aerospace sector based on compression moulding. Compression moulding is a reliable technique that can be well-controlled for high-volume production of high-quality components. Development of numerical tools and experimental methods led to optimisation of materials and processing.

The high-performance complex shapes required by the aerospace industry make joining techniques a critical factor to successful manufacture and use. The team chose induction welding that relies on eddy currents to heat the material. Following extensive numerical and experimental work, scientists built a new optimised, fully automated, continuous induction welding machine. Its excellent performance was confirmed by the mechanical properties of the welds. This is a key project result.

Three technology demonstrators for helicopters were designed and produced with the materials and methods developed within the scope of ECO-FAIRS. They were subjected to non-destructive inspections and complete evaluation of mechanical performance. An eco-assessment confirmed lower environmental impact compared to that of thermoset composites. The team delivered important quality control and characterisation methodologies to ensure certification that will be of particular relevance to the aerospace community.

ECO-FAIRS has made an important contribution to the aerospace manufacturing sector that promises to substantially enhance competitiveness and support the EU economy in a time of crisis. Implementation promises high-quality aerospace components at reduced cost and with lower environmental impact of both manufacturing and use.