Next-generation aircraft structures enabled by tailored friction stir welding and laser welding

Structural components of aircraft fuselages, such as frames and stringers, are predominantly manufactured from milled high-strength aluminum profiles. In the milling process of frame structures, particularly at in the area around emergency exit doors, approximately 98% of the raw material is removed. This results in high material and production costs, along with significant energy consumption and a poor CO₂ footprint. Despite these drawbacks, milling remains the standard manufacturing method, as the high-strength aluminum alloys commonly used (e.g. EN AW-7075 T651) are prone to hot cracking and therefore not suitable for conventional welding.
This study presents and evaluates weldable fuselage stiffening structures designed to reduce material usage and component mass (with weight savings of up to 4%), while enhancing mechanical performance (achieving stiffness increases of up to 11%) compared to conventionally milled components. Weldability is achieved through structurally optimized joint geometries, tailored friction stir welding (FSW) processes and specialized clamping devices. Additionally, innovative laser welding techniques employing dynamic beam shaping (DBS) are introduced. The proposed solutions for frames and stringers are based on single-sheet designs with load-adapted thickness distributions and weld configurations. Friction Stir Additive Manufacturing (FSAM) is employed to integrate fuselage doublers into highly stressed areas.
This work opens new perspectives for resource-efficient structural concepts and represents a key step toward weldable fuselage architectures. Initial prototype simulation and testing have demonstrated promising structural integrity. The proposed solutions offer strong potential for scalable and sustainable production in aerospace as well as the automotive and energy sectors.