EMOTION – Enhanced Mould for Thermoplastic Fuselage in and out of Autoclave Consolidation
The project provides a tool that enables the production of high volume half-shells from thermoplastic fibre composite. The tool is used in the CS2 joint project STUNNING, contributing to the Multi-Functional Fuselage Demonstrator.
Composite structures are used for latest airliner generation. Further improvement for the airframe lightweight structure shall be achieved by using thermoplastic based composite materials. While the use of carbon fibres as strong and stiff material remains the same, the matrix materials shall be changed to thermoplastics. This change is also motivated by potential improved end-of-life properties, e.g. meaning improved recyclability.
Lightweight structures are essential for the environmental friendly operation of airliners and in general mobility providers. Less weight, means more passenger or freight can be transported at same CO2 footprint. New propulsion technologies will not replace this need for lightweight structures. Instead, electrification and hydrogen technology in the area of propulsion require further improvements in lightweight construction to compensate for lower energy storage densities.
Composite structures are stacked from several thin plies which need to be consolidated to a solid and strong material. Consolidation means that a pressure of up to 10 bars and temperature up to 400°C is applied to the stacked material. Doing that, a shape-defining tool is required which resists the temperature and pressure applied by an autoclave.
The EMOTION consortium is researching durability and process suitability with the aim of achieving the best interaction between mold and component. During component manufacturing, the composite material is positioned at room temperature but need to be heated up to 400°C for consolidation later. The tool material (typically metal) as well as the composite material will expand and shrink during that operation. The difference in thermal behaviour causes the challenges. In the worst case the manufactured composite structure is affected by wrinkles. Wrinkles in the fibre architecture reduces the strength of a composite material.
Carbon composite materials itself creates due to their energy intensive production a relative high CO2 footprint. By using thermoplastic matrix materials, processing temperatures rise and therefore energy efficient processing technologies are requested to provide an overall benefit in terms of ecological footprint.
The project is therefore split into a near term and midterm technology approach. Processing in an AC is state of the art and can provide superior consolidation qualities. Processing out of an AC (ooA) is an objective for energy reduction, making thermoplastic composites even more competitive and providing a reduced ecological footprint.
The EMOTION project has shown at the end, that both approaches are based on same technological keys: 1) Use of special alloys for the mould skin addressing the CTE differences between tool and component 2) Multi material tool design capable to handle inhomogeneous thermal expansions. Both set up the base for an induction heated tooling system which can replace the AC operation.
