Ertragbare Strukturspannungen von lasergeschweißten Stahlblechen

In this research project the fatigue performance of some basic types of laser welded joints with a plate thickness of 0.8 mm and 2.0 mm was determined under constant amplitude axial fatigue loading. Additionally, some types of laser welded hollow sections were submitted to constant and variable amplitude torsion loading. It was found out, that the fatigue strength of laser welded parts is significantly higher than in the case of spot welded parts of the same size. All fatigue test results were given in terms of nominal stresses as well as in terms of structural stresses. The knowledge of the structural stresses is essential for a design engineer, as these values are taking into account the superposition of all stresses due to multiaxial loading cases and the stress distribution in a component due to a stress gradient or due to an irregular geometry. The improved fatigue strength of laser welded joints enables optimised light-weight constructions and will lead to a remarkable reduction of material, energy and costs.