The TANGO research programme led by Airbus recently achieved a key milestone when the largest ever composite outer wing box to be built in Europe successfully completed the most severe of the static tests at Airbus' Filton site in the UK.
TANGO’s objective is to find innovative, workable solutions that will result in 20 per cent reductions in both airframe weight and cost.
The ultimate load test examined the resistance of the wing box to loads of over 100 tonnes under simulated hot-wet conditions which are far greater than those that this component would experience in normal airline service. In addition, controlled defects were deliberately made during its manufacture to assess the robustness of the design. The successful results of these tests demonstrated conformity with early performance levels predicted during the detailed design phase.
Having completed this testing in June, the composite wing box is now undergoing a fatigue test programme during which the wing will be subjected to loading conditions equivalent to a life-time’s take-off, flight and landing cycles. In particular, this will allow an assessment of the wing’s resilience to damage.
To facilitate this, the wing will be subjected to various kinds of damage that would be typical of accidental damage inflicted on a wing during its operational life with some, but not all, of the damage being repaired in accordance with predefined repair procedures. The combined effects of the repairs, the unrepaired damage and the controlled manufacturing defects results in a far worse scenario than would ever be seen in-service, enabling the design team to fully understand the performance of the wing structure.
The challenges of building Europe’s first all-composite wingbox have necessitated the development of new engineering and manufacturing practices. Less-costly production processes have been used for the major components for example dry Non-Crimp Fabrics (NCF) that are combined with Liquid Resin Injection (LRI) or Resin Film Infusion (RFI) for the wing skins and spars. A highly-automated robotic assembly process has resulted in a radical reduction of labour intensive repetitive actions while at the same time avoiding a potential source of quality problems. The wingbox work package involves 21 partners from research organisations and industry drawn from across Europe, as well as Israel and Australia and is one part of the TANGO aviation research programme that is partially funded by the European Union.