1 Residual Stress Estimation of Welded Tubular K-joints under Fatigue Loads

In tubular joints, the hot spot stress concept is used to characterize the stress field at potential fatigue crack locations. The combination of determining stresses using the hot spot concept, with a reduction factor on fatigue strength is however not a satisfactory solution. In this paper, an overview of a on-going research project in which the overall phenomenon, including geometrical size effects, welding residual stresses and loading effects, is presented. Within this project, fatigue tests and residual stresses investigations are carried out on planar circular hollow sections (CHS) truss girders as well as on isolated K-joints. Residual stresses measurements aim to get intensity, variability with depth and influence of fabrication sequence. They are obtained using the incremental hole-drilling method