TWI-led project to advance laser welding in order to improve aircraft efficiency

The OASIS project will lead to the fabrication of two full-scale cargo doors without the use of rivets. (Credit: TWI) 

TWI (The Welding Institute), based in Cambridge, UK, is leading a new Horizon 2020 project to advance laser welding in order to improve the efficiency and cost of aircraft manufacturing.

The OASIS project, set to run for 30 months with a total budget of €1.4 million, involves six European partners alongside TWI and will demonstrate the ability to manufacture complex lightweight aluminium aircraft structures using advancements in both laser welding and friction stir welding (FSW).

The project is part of the EU’s Clean Sky2 research programme, which aims to develop innovative, cutting-edge technology to reduce the CO2, gas emissions and noise levels produced by aircraft, while also strengthening European aero-industry collaboration, global leadership and competitiveness.

Traditionally, riveting has been the primary method for joining aluminium structures in aircraft fuselage manufacture, with large commercial aircraft fuselages containing hundreds of thousands of rivets. However, this joining method is time-consuming, expensive and adds weight. It also places holes and point loads in cyclically pressurised structures, which can lead to long-term fatigue loading and corrosion.

The OASIS project will advance laser welding, FSW and friction stir spot welding (FSSW) to improve the manufacturing of aluminium structures by removing the need for rivets, and will lead to the fabrication of two full-scale cargo door demonstrators for validation.

In contrast to riveting, laser welding, FSW and FSSW offer a lighter-weight distributed load path with the potential for improved structural stiffness and strength. With no holes and a smoother, aerodynamic surface, these methods create a more efficient and cheaper technique that should reduce the requirement for inspection and maintenance.

The lack of riveting is expected to reduce weight by 10 per cent, reduce joining time by 40 per cent, save the use of consumables such as sealants, and lower the number of protective organic layers required to protect against corrosion.

The lighter weight and improved aerodynamics of the rivetless construction will also lead to increased fuel efficiency to improve the general cost-effectiveness of aircraft operation, help the environment by reducing CO2 emissions and save 30 per cent on material usage compared with mechanical fastening/CNC machining.

In addition, the OASIS project will undertake simulation and modelling of the effect of welding on structural integrity, study residual stress and distortion of the full structure, and take the input data from weld test coupons.

The developments made within the project are expected to lower the cost of travel, reduce lead times for product development, cut hazardous emissions and contribute to the need for more efficient and environmentally-friendly air transport. OASIS developments will also be transferable to the structural assembly of other aircraft parts and other industrial applications to allow for further advances and job opportunities.

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Applications, Welding, Aerospace