Effect of Transverse Restraint on Welding Residual Stress in V-Groove Butt Welding

When evaluating the safety of steel structures, welding residual stress is used as the secondary load and if there is any restraint, the yield stress of the base material is used for secondary load, regardless of the size of the restraint. Of late, as the yield stress of members is increasing with the increase in the use of high-strength steels, the proportion of the residual welding stress in the total load during the evaluation of the safety of structures is increasing. Therefore, it is necessary to investigate the effect of the size of the restraint on the residual welding stress, determine reasonable residual stress according to the size of the restraint, and apply the residual stress as a secondary load. To investigate the effect of constraint conditions on residual welding stress, thermoelastic-plastic analysis was performed for different member thicknesses, yield stresses, and constraint sizes. The restraint did not affect the residual stress in the direction of the weld line but did affect the residual stress in the direction perpendicular to the weld line. The restraint moved the tensile stress to the compression stress in the direction perpendicular to the weld line at the first layer of the weld and moved the compression stress to the tensile stress at the middle and final layers of the weld. The change in residual stress was the largest in the middle of the weld.