The European and global aircraft market will benefit from new cost effective manufacturing routes for aerostructures, ensuring optimal material usage and maintain its competitiveness. The impact of the uptake of the optimised welding techniques (FSW, FSSW and LBW) for assembly of structural aircraft parts will enhance improved aerodynamics and light-weighting which subsequently will improve fuel efficiency and global competitiveness of the industry. Also in terms of productivity, joining using rivets is more time consuming than using welding approaches. In the case of rivets, holes need to be drilled and deburred prior to installing the rivets and a “redressing” step is required after the rivets are in position. Moreover rivetless assembly will enable the usage of “leaner” parts. Delivering a new cost effective manufacturing route for assembly of aircraft parts (cargo door) to the topic manager and the European aerospace industry, will make a contribution to the range of innovations being addressed within the Airframe ITD initiative in Clean Sky 2 that includes:
- The use of SSFSW (including corner welding) and RFSSW of stiffeners and frames to skins in a T-configuration, with material combination of AA2000 and AA7000 series alloys.
- The utilisation of the AA5xxx series alloy, specifically the AA5028 Al-Mg-Sc alloy, welded using LBW without a filler addition which would greatly simplify manufacturing.
- The use of SSFSW to weld curved panels in a butt-joint configuration.
- The implementation of numerical modelling to model the welding processes as their effects on structural integrity, distortion and residual stress for welded cargo doors.
- The implementation of a Digital Twin to accurately predict the associated costs for the rivetless assembly when fabricating using welding technologies.
Overall the developments have proven that by using welding techniques (FSW, FSSW and LBW), “leaner” parts can be used to fabricate aerostructures for fuselage applications, leading edge, wing panels, nacelles and doors. The light-weighting is achieved by eliminating rivets, sealant and flanges, reduced frame thickness, and the ability to have continuous joints, rather than spot joints. With the use of welding techniques to produce rivetless assemblies, joining time could be reduced, by 75%, than when using manual riveting.
The development of OASIS technologies, combined with other fuel consumption reduction steps and engine developments being undertaken in the JTI, will result in the existing fleet of civil aircraft being able to be replaced with more fuel efficient alternatives, and ultimately supporting the fabrication of a new generation of zero-emission aircraft in the next decade.
