Introduction of Friction Stir Welding on front fuselage primary structures of aircrafts

Friction Stir Welding is a solid phase joining process commonly used in aluminium industry. Contrary to fusion welding process, FSW allows welding of 7xxx and 2xxx alloys, frequently used in aeronautic industries.... [ view full abstract ]

Friction Stir Welding is a solid phase joining process commonly used in aluminium industry. Contrary to fusion welding process, FSW allows welding of 7xxx and 2xxx alloys, frequently used in aeronautic industries. Repeatability, low cost and high mechanical properties are the main qualities which make FSW a good candidate to replace splice assemblies on aircraft structures. Fastening assembly removal should enable substantial weight and cost saving.

STELIA is French aerostructures leader and a major player worldwide for design and production of equipped fuselages. STELIA produces every year more than 650 noses and fuselage sections and 6 million elementary parts and panels. For 4 years, STELIA leads a research program (Optimized Front Fuselage Structure with Enhanced Technologies) dedicated to FSW technology. The main challenges are to introduce FSW on a front fuselage panels of civilian aircrafts. This area is characterized by a double curvatures shape and is submitted to impacts (bird, hail,…). STELIA has used support of AIRBUS GROUP INNOVATION France, AIRBUS HELICOPTER Marignane and the French Welding Institute to take benefit of their strong FSW return of experience built with numerous previous R&T projects.

Two welding configurations are considered : butt joint welding in order to replace the longitudinal lower unit splicing and lap joint welding to assembly stringers on upper cap panels. Mechanical behaviour (fatigue, static and damage tolerance), cost analysis, corrosion behaviour, manufacturing tools and parameters are studied. Two scale 1:1 demonstrators (a welded upper cap panel and a welded lower shell panel) have been designed and welded. A bird strike test has been realized in June 2014 on the upper cap demonstrator to assess the resistance to dynamic impact of FSW joints.