F. Eberl, Alcan Rhenalu, Issoire Cedex, France; I. Bordesoules, Alcan CRV, Voreppe, France; F. Bron, J. C. Ehrstrom, Alcan, Voreppe, France
The use of monolithic structures shows a great interest for very competitive weight/cost performance balances in wing or fuselage aircraft structures. In particular for business jet wings, integral structures are widely used due to their stiffness and cost efficient manufacturing. Even for larger regional jets, monolithic structures were selected for their design flexibility.For compression loaded upper wings, various buckling modes are the limiting property. Integral machining of monolithic plates allows to integrate particular design features in order to increase the stiffness of the wing and to optimize the buckling behavior.
Well selected design features are also of great interest for damage tolerant dominated areas. Although endurance fatigue is naturally improved compared to a built-up structure, the design needs to be optimized for the fatigue crack propagation performance. Innovative structural designs integrating low cost reinforcements allow to exploit the entire benefit of a full integral wing.
In order to optimize the material use by conserving the full advantage of monolithic structures, modern assembling techniques as friction stir or laser beam welding can be used. Even more competitive cost reduction can be reached by thinking of the global life cycle and the supply chain management. From construction to dismantling, aspects as recycling are taken into account.
Last not least, the choice of the advanced aluminum alloy plays a key role for the property balance of the part to be designed. A large alloy portfolio and particularly alloys developed for monolithic structures allow to reach a high performance balance for cost effective metallic aircraft structures.Examples illustrating the specific areas of design, recycling, supply chain and optimized materials choice will be shown for various aircraft structural parts. Comparisons to today’s flying structures will be mentioned as baseline in order to better appreciate the step-change which has been made in the last decade.
Summary: The use of monolithic structures shows a great interest for very competitive weight/cost performance balances in wing or fuselage aircraft structures. In particular for business jet wings, integral structures are widely used due to their stiffness and cost efficient manufacturing. Even for larger regional jets, monolithic structures were selected for their design flexibility.
For compression loaded upper wings, various buckling modes are the limiting property. Integral machining of monolithic plates allows to integrate particular design features in order to increase the stiffness of the wing and to optimize the buckling behavior.
Well selected design features are also of great interest for damage tolerant dominated areas. Although endurance fatigue is naturally improved compared to a built-up structure, the design needs to be optimized for the fatigue crack propagation performance. Innovative structural designs integrating low cost reinforcements allow to exploit the entire benefit of a full integral wing.
In order to optimize the material use by conserving the full advantage of monolithic structures, modern assembling techniques as friction stir or laser beam welding can be used. Even more competitive cost reduction can be reached by thinking of the global life cycle and the supply chain management. From construction to dismantling, aspects as recycling are taken into account.
Last not least, the choice of the advanced aluminum alloy plays a key role for the property balance of the part to be designed. A large alloy portfolio and particularly alloys developed for monolithic structures allow to reach a high performance balance for cost effective metallic aircraft structures.
Examples illustrating the specific areas of design, recycling, supply chain and optimized materials choice will be shown for various aircraft structural parts. Comparisons to today’s flying structures will be mentioned as baseline in order to better appreciate the step-change which has been made in the last decade.
