R. Alderliesten, R. Benedictus, Delft University of Technology, Delft, Netherlands
A current trend in aviation is the increase of composite applications in primary aircraft structures. Especially for wing structures, the development seems to aim for composite materials, while aluminium suppliers improve the properties of new aluminium alloys to remain competitive.
The authors believe that aluminium in future aircraft structures can only be competitive to composite materials, if a similar composite approach will be followed. This means that instead of the conventional monolithic structural materials, structural materials should be developed that are composed of different engineering materials tailored towards the specific application. This composite approach must be explored significantly further than the current state of technology, mainly represented by developments on integral monolithic structures, reinforcing patch technology and damage containment features.
A proven Fibre/Metal composite technology is the concept of Fibre Metal Laminates (FML’s), of which Glare (aluminium 2024-T3 with S2-glass/epoxy) has found its first large scale application in the upper fuselage skin structure of the Airbus A380. This FML is characterised by its standard lay-ups, which has been listed as six Glare grades. A full Fibre/Metal composite technology will aim for further tailoring towards the application, giving the designer full freedom in the material design.
TUDelft has composed extensive amount of knowledge on the concept in the development phase of Glare. Despite the limiting literature published due to the restrictive nature of the development program at that time, a variety of analytical models are available that describe the static, fatigue and residual strength mechanisms. These prediction models enable with their accurate predictive power the further development of this composite concept and as result of their generic nature, make further extension of the models to new concepts possible.
The paper will highlight the developments in this field by TUDelft and will try to identify the way towards future developments and applications.
Summary: Future aircraft structures require new Fibre/Metal composite techologies to significantly improve the structural performance as compared to current structures and technologies. A proven Fibre/Metal composite technology is the concept of Fibre Metal Laminates (FML’s), of which Glare (FML variant with aluminium 2024-T3 sheets and S2-glass/epoxy layers) has found its first large scale application in the upper fuselage skin structure of the Airbus A380. The paper will highlight the developments with respect to these technologies by TUDelft and will try to identify the way towards future developments and applications.
