Improving thermoplastic composites for next-generation fuselage
Thermoplastic composites (TPCs) are an advanced material class poised to be widely used in the aerospace industry. TPCs offer greater toughness and increased impact resistance to thermosets – the current industry standard material – which could reduce maintenance operations over an aircraft’s operational lifetime. TPCs are challenging and expensive to make, however. They require very high processing temperatures close to 400 °C to shape them before they cool into place. The quality of the parts is also affected by the heating and cooling speed, which can be tricky to manage on large parts with local thickness changes. “At this temperature level, the range of applicable ancillaries’ materials is very limited, expensive and still challenging to use on double curved parts with stiffening elements,” explains Guillaume Fourage, an engineer at ESTIA (website in French) and FRAMES project coordinator. In the EU-funded FRAMES project, researchers at ESTIA developed a new manufacturing approach to support the development of future advanced aircraft fuselage and empennage with TPCs.
A multipart strategy for TPC production
Rather than one specific manufacturing approach, the FRAMES team devised a series of solutions for a wider range of processes involved in rear fuselage manufacturing. These included: a simulation tool to predict processing temperatures during skin panel manufacturing by automated fibre placement; high-rate manufacturing solutions for stiffeners (structures added to aircraft fuselage to provide support); and a self-heated tool to assemble skin and stiffeners. To produce complex shapes of stiffeners, the FRAMES team improved certain manufacturing processes such as hot stamping (for shaping composites), continuous compression moulding (a method for creating TPCs) and fibre placement. And finally, they manufactured a new tooling set with integrated heating and cooling channels to shape the TPCs more effectively. This physical metallic tool developed in the FRAMES project for the production of complex stiffeners represents a step forward in the processing of TPCs. It has been built to manage thermal expansion between the different assembly components and ensure a precise temperature control over the full production cycle, Fourage explains.
Simulating for improved manufacturing precision
The simulation tool developed within FRAMES provides the capacity to precisely control the amount of heat energy delivered to the material during fibre placement. This tool can be used to optimise the moulding processes for TPCs, for example by increasing fibre placement speed while keeping control of energy consumption. “We have managed to produce highly curved stiffener profiles, including thickness variations and within a competitive cycle time,” says Fourage.
Bringing TPCs into Europe’s aircraft
The solutions developed in the FRAMES project will soon be used in advanced demonstrator platforms, trials involving major aircraft companies across Europe. “The project outcomes will support the manufacturing of a scale one co-consolidated fuselage panel, leveraging weight savings and production rates,” adds Fourage. Thanks to the knowledge gained through FRAMES, the team will now continue to refine their process parameters, and help support their customers in meeting performance and environmental targets. “I would like to thank the team for their efforts and commitment over the last two and a half years, keeping focused on project objectives despite challenging moments,” concludes Fourage. “Beyond its technical accomplishments, the FRAMES project has also been a great European collaboration story.”
Keywords
FRAMES, fuselage, aerospace, advanced, composites, production, simulation, manufacturing
