Residual stress effects on fatigue behaviour of welded T-joint: A finite fracture mechanics approach

Abstract

The effects of residual stresses on fatigue behaviour of welded T-joint are investigated based on a coupled stress and energy criterion which requires two fundamental material parameters: the fatigue threshold value and fatigue limit. Finite element analysis of the welding process determines the residual stresses. It is found that the residual stress effects on fatigue strength are significant for R<0.5 and negligible for R≥0.5. The presence of residual stresses may change the crack deflection direction and lead to the decrease of ductility. The predicted fatigue strength is in good agreement with FAT value recommended by IIW.