The Airbus A350 XWB performed its maiden flight on June 14, 2013 from Toulouse, France before its fly-by at the Paris Air show. Aboard were a number of composite developments, starting with overall airframe solutions to its all-new fuselage. With this model, Airbus opens a new chapter in the usage of CFRP, using the carbon fibre reinforced plastic for wings, the centre wing box and keel beam, tail cone, skin panels, frames, stringers and doublers and doors.
The A350 XWB, which dazzled visitors with a Paris Air show fly-by, performed its maiden flight on June 14, 2013 from Toulouse. (photos: Airbus)
Intelligent airframe
More than 70% of the A350 XWB’s airframe is made of advanced materials – bringing together composites, titanium and advanced aluminium alloys. Airbus’ extensive application of composites – comprising 53% of the overall airframe (compared to 11% in the A330) – benefits from the design and manufacturing advances for such lightweight, strong and durable materials. Their advantages on the A350 XWB begin with reduced development times and higher production rates on the final assembly line, while contributing to lower overall aircraft weight, along with proven in-service durability, reduced corrosion and fatigue, as well as lower maintenance costs.
A350 XWB 32m by 6m lower wing cover, largest single composite part in commercial aviation at the wing factory Broughton, Wales, UK.
The supplier of the carbon fibre prepreg for the composite primary structures of the A350 XWB is Hexcel. The structures made with HexPly M21E prepreg systems and HexTow IM carbon fibre include the entire fuselage panels, keel beam, the entire wing covers, wing spars, centre wing box and empennage.
The A350 XWB’s airframe consists of more than 70% composites, titanium and advanced aluminium alloys – resulting in a lighter aircraft as well as a 25% step change in fuel efficiency.
Traditionally, an aircraft’s metallic fuselage is used as part of its electrical network. As a carbon fuselage is not as conductive as one made of metal, Airbus had to identify a new approach – leading to what is referred to as the “electrical structural network”, which is like a network of parts throughout the aircraft forming the return circuit for electronic systems and giving protection for systems from electromechanical interference.
Completed curing of the first panel of the longest section of the A350 XWB’s carbon fibre fuselage (19.7m long, 77m2) realised by Spirit AeroSystems in Kinston, North Carolina, USA. (photo: SpiritAeroSystems)
Four-panel concept
The A350 XWB’s major fuselage sections are created by the assembly of four large panels each, which are joined with longitudinal riveted joints. According to Airbus, one advantage of this approach is a better management of tolerances when the jetliner’s composite fuselage sections come together on the A350 XWB Final Assembly Line in Toulouse.
The four-panel concept is also said to provide considerable weight savings, as the use of longer panels requires fewer circumferential joints – which are quite heavy – and relies more on lighter longitudinal joints. This weight saving also results from better optimisation of each panel for its application. The use of fewer, longer sections also means fewer joints overall – which are placed for load and weight optimisation. Another benefit is better reparability in operational service, as an individual panel can be replaced in the event of significant damage – avoiding major repair work that could require extensive composite patching.
Material breakdown for the Airbus A350 XWB air frame (source: Airbus)
CFRP in the fuselage
Built with carbon fibre reinforced plastic (CFRP), the A350 XWB’s all-new fuselage supports lower fuel burn, easier maintenance and increased resistance to corrosion. The CFRP fuselage (40%) plus aluminium/aluminium-lithium alloys (55%) and titanium alloy components (5%) result in lower fuel consumption and easier maintenance than previous solutions. These materials are said to reduce the need for overall fatigue and corrosion maintenance tasks while enhancing the jetliner’s overall operating efficiency.
A composite fuselage section produced by Spirit AeroSystems in North Carolina, USA is shown ready for delivery to Airbus.
A first in composite wings for Airbus
Most of the A350 XWB’s wing is made of the lightweight carbon composites, including its upper and lower covers – measuring 32m long by 6m wide, making them the largest single civil aviation parts ever made from carbon fibre composite material. The wing’s advanced structural design, combined with its aerodynamics, is a significant contributor to the jetliner’s 25% fuel-saving performance.
The initial wing for Airbus’ A350 XWB has been delivered to the jetliner’s final assembly line in Toulouse, France, where it will be fitted on an airframe for ground-based structural tests.
Recycling of carbon composites
With its A350 XWB, Airbus has for the first time demonstrated the feasibility of carbon composite recycling with commercial aircraft, according to the company. The recycling process is completely automated, from the separation of the composite components from the other constituents of the aircraft, to the final extraction of the carbon fibres for recycling. Ongoing research and development is underway with Airbus and several partners to further refine the technology and develop applications, marking steps toward making composite recycling a reality.
www.airbus.com
www.hexcel.com
www.spiritaero.com
