The effect of geometrical parameters, corrosion and residual stresses on the fatigue behaviour of welded structures

This paper addresses several practical problems concerning fatigue behaviour of welded structures in both air and corrosive environments. Initially, a numerical model has been developed using linear elastic fracture mechanics (LEFM), weight function technique and superposition principle to assess fatigue behaviour of butt-joints in air environment subjected to various weld geometries (including undercut) and residual stresses. This model has also been used for the assessment of corrosion fatigue of welded joints in the corrosive environment by modifying the Paris’ crack growth law. It has been found that the fatigue life and fatigue strength of butt welded joints in air and corrosive environments can be improved by decreasing the tip radius of undercut at weld toes or eliminating the weld toe undercut completely.