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In current aircraft programs as Airbus A318, A340 or A380 laser beam welded panels are already assembled in the fuselage belly area by using high strength 6xxx alloys as 6056 or 6013.
Optimized design concepts and advanced weldable materials allow significant weight savings for future metallic fuselage structures. Thanks to new manufacturing technologies on top of weight savings major cost savings can be reached due to increased joining speed for skin-stringer joints.New Al-Cu-Li fusion weldable alloys show improved strength-toughness balances by decreased density compared to the 6056 baseline. The so-called WeldaliteÓ alloys allow dissimilar material combinations, so that new assembling concepts can be introduced for even higher weight savings for welded fuselage panels without any supplemental cost compared to similar material combinations. Thanks to metallurgical modeling, very low hot cracking sensitivity can be reached for industrial set-ups.
Alloys as 2198 produced as fuselage sheet or 2196 elaborated as extruded section will be presented in welded configurations typical for welded fuselage shells. These materials will be compared to the 6056 sheet + 6056 stringer baseline and other high performance materials as 2022 or 2139. All materials tested have artificially aged final tempers, so that welding in T3 or T6/T8 is possible. Final properties of different processing routes will be compared.
In order to reduce cost, longitudinal friction stir welded joints (skin-skin butt joint) are of great interest. The previously mentioned materials developed for fusion welded applications have been friction stir welded. In order to define the best cost/performance balance, different processing routes have been evaluated.
In summary, the potential weight saving for welded monolithic fuselage structures thanks to optimized design concepts will be reminded. Different welded material combinations using Al-Li-Cu or other high performance materials as 2022 or 2139 will be discussed for fusion and friction stir welded processes.