Product Code: ICAL08_1804

Progress in Laser Beam Welding of Aircraft Fuselage Panels
Authors:
Dirk Dittrich, Fraunhofer Institute - Material and Beam Technology; Dresden Germany
Bernd Winderlich, Fraunhofer Institute - Material and Beam Technology; Dresden Germany
Berndt Brenner, Fraunhofer Institute - Material and Beam Technology; Dresden Germany
Eckhard Beyer, Fraunhofer Institute - Material and Beam Technology; Dresden Germany
Jens Hackius, Airbus Deutschland Gmbh; Bremen Germany
Presented at ICALEO 2008

The most challenging objective for future metallic fuselages is to reduce weight and to obtain lower production costs in comparison to CFRP-Materials. On the metallic side, Airbus established successful laser beam welded stringer-skin-joints in the lower fuselage to overcome current limitations of conventional riveting techniques. To extend the advantages of laser beam welding (LBW), it is proposed to weld also clip-skin connections and to join single panel to greater units. Compared to stringer-skin-joints, longitudinal skin-skin connections in the fuselage are exposed to higher structural loads, caused by the circumferential stress. Beyond this, skin skin joints have to fulfil all requirements of damage tolerance, fatigue behaviour and stiffness.The paper presents the results of a study to improve damage tolerance for laser beam welded skin-skin-joints, concerning a new weld seam path in relation to the strength mismatch of the weld. Special attention will be focussed on the damage tolerance behaviour. The obtained advantages of the skin-skin-joints are: a damage tolerance behavior of LBW joints comparable to the base material, a weight saving potential of at least 10% compared to riveted structures, enhanced structural properties such as stiffness and corrosion resistance compared to conventional riveting techniques. A further benefit is the possibility to transfer the solutions for improved damage tolerance to other welding techniques such as friction stir welding (FSW). First promising results show that the damage tolerance between LBW and FSW is almost comparable.