Fatigue assessment of cruciform joints welded in different positions

Welded structures are frequently used in today's metal industry. Since fatigue
is still one major reason of failures, investigation in this field is of interest to engineers.
In this study both numerical and experimental methods are employed to perform a fatigue
evaluation concerning local weld geometry. The emphasis was on quantifying the weld
toe radius as a feature in quantification of weld quality. Three different welding positions
which have been led to different toe radii were analyzed. Each batch contained 12
specimens manufactured in cruciform joint and has been tested in non-load carrying
status. Finally, the results of tests were compiled in Wöhler (S-N) curve and compared to
reference curves introduced by IIW (International Institute of Welding). Results of this
study show that local weld geometry has remarkable influence on strength of welded
structures. It can be concluded that specimens with larger toe radii had more fatigue
strength - as it was expected from the theory.