Abstract
This work deals with the development of laser beam welded (LBW) fuselage structures made of Titanium alloys. State of the art disk and fiber lasers have been employed to weld T-joints between Titanium Grade 2 sheets and Ti-6Al-4V Grade 5 stringers. Both skin sheet and stringers had a thickness of 0.8 mm. Optimum LBW parameters and process window have been determined for both laser sources with 400 and 500 microns spot size, respectively. Full penetration welds and minimum underfills (less than 80 μm) have been achieved without the addition of filler metal.
Due to the reduced thickness and stiffness of the skin, LBW led to significant distortion in samples with multiple welded stringers. A subsequent laser straightening (LS) process has been applied in order to reverse welding induced distortions.
The results show the feasibility of manufacturing these aircraft structures based on T-joints between Titanium alloys. The work is completed with the analysis of ongoing developments to ensure required quality standards in large 3D HLFC structures, including seam tracking and process monitoring.
