Composites with greater benefits
Composites with two or more individual materials have become integral parts of aircraft components, enabling them to combine important properties such as strength and low weight. Hybrid structures combining conventional carbon fibre-reinforced plastic (CFRP) laminate with inserts such as rubber or nanoparticles can improve vibroacoustic damping. However, this typically comes at the cost of mechanical performance. The EU-funded 'Hybrid laminates. Industrialization for aircraft nose fuselage' (HYBRIA) project set out to overcome this issue with materials and industrial production processes for future aircraft that meet both airline and customer demands. One of the main targets of the EU's Clean Sky initiative partnering public and private organisations is to reduce aircraft weight to reduce fuel consumption and emissions. Most commonly, propagation of aircraft noise and vibration is minimised using add-on parts that increase weight along with materials and labour costs. Integrating vibroacoustic damping functionalities into structural components will reduce redundancies and help meet that goal. Researchers produced three curved stiffened panels made of hybrid skins and co-cured stringers (stiffeners to which the skin is attached) of different shape sections. The geometries were representative of the Clean Sky Green Regional Aircraft (GRA) cockpit fuselage. The team investigated several different manufacturing methodologies during the production of demonstrators to select the best concepts for eventual production of the entire GRA cockpit fuselage. The quality of the test specimens was assessed using a combination of non-destructive testing and dimensional analyses. HYBRIA proved the feasibility of embedding acoustic damping materials in a CFRP structure with an industrially relevant manufacturing process and without significantly affecting mechanical properties of the structure. Further, scientists produced innovations in tooling design and manufacturing, simplifying the tooling and assembly process and reducing materials usage. The one-shot manufacturing process enables co-curing the hybrid skin and stiffeners for significant reductions in energy and materials usage. Taken together, the manufacturing technology and configuration will support sustainable and cost-effective manufacturing as well as decreased weight, fuel consumption and emissions associated with air transport. These far-reaching benefits will boost the competitiveness of the industry, minimise global climate change and make travel more comfortable for passengers.
Keywords
Composites, vibroacoustic, damping materials, fuselage, aircraft
