Effects of residual stresses on fatigue crack initiation of butt-welded plates made of high strength steel

The fatigue resistance of welded connections made of high strength steel is one of the challenging issues for wider use of HSS in construction. The residual stress of a V-shaped butt welds on a plate made of high strength steels are thoroughly analysed by modelling of the welding process based on subsequent thermal analysis and mechanical stress analysis by implementing kill/birth strategies. The predicted residual stresses are validated by comparing the FE results and experimental results obtain by neutron method available in the literature. A user-defined fatigue damage initiation criterion based on Smith, Watson, and Topper (SWT) parameter is implemented in ABAQUS to predict the fatigue crack initiation and life time. The residual stress effect on fatigue crack initiation of butt-welded plates is investigated by considering no effects of residuals stresses and by considering the numerically predicted residual stress distribution due to welding. The results clearly showed influence of the residual stress distribution on the fatigue crack initiation. The fatigue behaviour of butt-welded plates considering the numerically defined residual stress show better agreement with experimental results than the residual stress-free model.