| Successful aircraft design incorporates a finely | | | | number 1 are stiffened with welded longitudinal |
| balanced blend of high-tech materials, structural | | | | stringers. Much is made of the increasing use of |
| advances, and traditional design know-how. Aircraft | | | | composites in aircraft structural design. Primarily, |
| shape is now optimized for all airframe components | | | | structures made of aerospace composites are weight |
| using computational fluid dynamics. Computational fluid | | | | saving. In the A380, an enormous belly fairing is |
| dynamics can cut drag by several percent. | | | | formed from a series of panels made up of a Nomex |
| The Airbus A380, for example, with its sheer scale, | | | | honeycomb and hybrid epoxy skin sandwich. An |
| its double-decker configuration and a wealth of new | | | | aluminium substructure that supports these panels |
| materials, such as GLARE and reinforced | | | | helps transfer some of the fuselage loads to the |
| thermoplastics. The aircraft also features | | | | fairing by deformation between the primary structure |
| carbon-fibre-reinforced plastic frames in the tail cone | | | | of the fuselage and the belly fairing support structure. |
| section and, never used in aircraft design before, | | | | A dome-shaped carbon-fibre-reinforced plastic |
| welded stringers in the lower fuselage. | | | | rear-pressure bulkhead separates the tail section |
| A design service goal is often set in advance. | | | | from the rest of the aircraft. |
| Advanced aluminium alloys form the semi-monocoque | | | | Physically smaller bits of the structure can be the |
| structure of the fuselage, while the skins are | | | | most complex aircraft assemblies. Loaded frames, |
| chemically milled or machined to reduce weight. | | | | which support the attachment for the massive |
| GLARE, "GLAss-REinforced" Fibre Metal Laminate | | | | vertical tailplane, are machined from high strength |
| FML, is used for the upper and lateral fuselage skins | | | | aluminium alloys, while weight-saving resin transfer |
| of the forward and aft section above the main-deck | | | | mouldings are used for less loaded frames. A titanium |
| level. Welded stringer panels are used in the lower | | | | rear fairing covers the aft-facing APU exhaust, while |
| fuselage sections below the main deck floor. | | | | the compartment itself is lined with firewalls made |
| Aircraft stress analysis. | | | | from titanium sheets. So, it is the combining of |
| Stresses have to be calculated for aircraft structural | | | | accumulated knowledge about available materials and |
| design. They are prevalent at cutout surrounds | | | | their properties that is the skill of the designers and |
| around doors and hatches, the wing root area, nose | | | | the complex combinations that now make up the |
| and centre fuselage, in other words, pressurised | | | | most advanced passenger aircraft. Massive wings, |
| areas. | | | | each supporting two engine pylons have now come a |
| In the A380, the fuselage containing the flight deck, | | | | long way from the concept of a rolled tube of |
| crew rest area, electronics bays, and passenger door | | | | aluminium with stringers inside. |