Title: Investigations on the influence of angular and linear misalignment on the fatigue strength of HFMI-treated structural steel butt joints
Abstract: <title>Abstract</title> The effect of High Frequency Metal Impact (HFMI) treatment on the fatigue resistance of structural steel S355 butt welds with macro geometric imperfections outside of the usual fatigue design limits was investigated. Thin-walled specimens were manufactured with different degrees of angular and linear misalignment and fatigue tested in the as welded and HFMI treated condition. The fatigue test results show that HFMI treatment can compensate the fatigue-reducing effects of macro geometric imperfections, but also that linear and axial misalignment do not reduce the fatigue strength of butt welds as severely as rules and guidelines suggest. Numerical analysis shows that the application of the notch stress approach according to current standards and guidelines delivers conservative assessment results, which might not always be representative for the actual fatigue strength benefit that can be gained by HFMI treatment.