PEEK fitting in the aircraft door of the Airbus A350-900
Airbus Helicopters is replacing aluminum in a fitting in the aircraft door of the Airbus A350-900 with a high-modulus, carbon fiber-reinforced high performance polymer. The brackets, now manufactured from PEEK (polyetheretherketone), has been developed by Airbus Helicopters and is in serial production for commercial use after receiving the relevant component qualification. The successful substitution of metal has resulted in a 40% reduction in weight and costs. The injection-molded part replaces the higher cost manufacture of the bracket machined from an aluminum block.
The fiber-reinforced polymer (FRP) structure of the A350 XWB’s aircraft door uses an outer skin coupled with a bracing structure on the inside. A fitting, now manufactured from Victrex PEEK 90HMF40 thermoplastic, connects the outer skin to points on the internal bracing structure. The two components form a box-type support structure to exploit the maximum geometrical moment of inertia.
“In terms of the standard load case, i.e. the internal cabin pressure, this point-type joint reduces the deformation on the outer skin, thereby maintaining the aerodynamic quality of the aircraft door. All components in the aircraft door are of a singly-redundant design. If a component near the bracket fails, the bracket will provide an alternative path for transferring structural loads and is therefore part of the aircraft’s primary structure”, explains Christian Wolf, Head of Airplane Doors Research and Technology at Airbus Helicopters.