Investigation on the Residual Stresses in a Welded Longitudinal Gusset Joint Using Computational Weld Mechanics and Qualitative Barkhausen Noise Analysis

Abstract The effect of residual stresses on the fatigue performance of metallic materials has been recognised for decades, and they can be considered in fatigue assessments, for example, by conducting mean stress corrections. However, based on simulations and in-situ field measurements, there might be considerable variation in the residual stresses after fabrication, introducing uncertainty in the determination of fatigue life assessments. To fully utilise the fatigue capacity of welded structures, the uncertainty related to the residual stress state must be addressed. In specific fatigue critical areas, unfavourable high tensile residual stresses can be diminished by using local post-treatments, such as thermal stress relief techniques and/or mechanical treatments. However, in larger, highly stressed weldments, postweld treatments are neither practical nor cost-effective, creating a need for more accurate prediction or determination of residual stresses. In this study, the welding of a longitudinal gusset joint was simulated using finite element modelling, considering different mechanical boundary conditions and the geometrical stiffness of the joint. Both factors were found to affect the resulting residual stress distribution. Additionally, the suitability of the Barkhausen noise method for qualitatively verifying the residual stress state in welded structures was investigated.