Perhaps the best known technological innovation aboard the A380 is the Glare (glassfibre reinforced aluminium) composite material which will be used for much of the upper fuselage skins.
Manufactured by Stork Aerospace of the Netherlands, the material is the culmination of 20 years of development work begun by Delft University of Technology and the Netherlands National Aerospace Laboratory (NLR).
Glare offers 15-30% weight savings over aluminium, and boasts excellent fatigue properties. Composed of alternating layers of four or more 0.38mm (0.015in) aluminium sheets and glassfibre reinforced bond film, the material thickness can be varied by adding sheets to match local property requirements.
"The glassfibres function both as a load path and as a crackstopper between adjacent aluminium layers," says Maarten van Mourik, director of Glare metalbonding at Stork Aerospace. Corrosion resistance is also increased relative to aluminium, he adds, with corrosion unable to penetrate the glassfibre layers.
The material can be cut, drilled, formed and milled in the normal way during manufacture, says Stork, which will use a five-axis milling machine to shape door and window cutouts. "The material can be treated as aluminium by the operator for repairs," says Kees de Koning, president of Stork Aerospace. "We're still defining inspection intervals, but we know we're conservative if we stick to those for aluminium."
Altogether the A380-800 will incorporate 27 Glare skin panels covering a total area of 469m2 (5,042ft2). Twenty-two of the panels are being manufactured by Stork at its new €40 million ($46 million), 12,000m2, facility at Papendrecht, with the remainder being fabricated under licence by Airbus at its Nordenham plant near Hamburg as a second source.
De Koning says the upper front and rear fuselage makes best use of the material's tensile strength properties. "The shear loads in the centre fuselage are too high for current Glare configurations," he says. However he doesn't rule out more widespread application on future A380 variants as the material's properties can be tailored to different requirements.
A thickness increase of a single aluminium sheet can be accommodated internally in the panel without significant surface effects, while additional Glare panels are bonded to the skin panels around door cutouts for more substantial reinforcing.
Incorporating so much of a new uncertificated material on the aircraft required an immense amount of trust on Airbus's behalf. De Konig says confidence was based largely on experience with A340-500/600 wing leading edge J-nose work, "where we brought new thermoplastics to the aircraft". Stork also builds the A380's J-nose, which stands 1.5m (4.9ft) tall at its inboard edge.
Testing of the "Megaliner" fuselage test piece at Airbus's plant in Frankenwerder near Hamburg also contributed to confidence. This was a 20m-long fuselage section roughly representative of the eventual A380 cross-section which incorporated aluminium and Glare as well as Glare stringers and doublers.
De Koning says Stork "brings new technology to the A380, technology that Airbus doesn't have". Stork is now close to completing delivery of the full shipset of Glare panels to Airbus Deutschland for the first flight test aircraft, and hopes to have its Papendrecht manufacturing facility fully operational by September.
Source: Flight International
