Cracks growth in S355 steel under cyclic bending with fillet welded joint

This study describes the results of tests on the fatigue crack growth for constant moment amplitude under cyclic bending in the ferritic-pearlitic structure. The tests were performed under constant value of the stress ratio R and at load frequency 28.4 Hz. Plane specimens with stress concentrators in form of the external two-sided blunt notches and fillet welded joint were tested. The fatigue crack propagation life has been calculated using fracture mechanics approaches and boundary element method. It has been found that the imposed welds significantly lengthened the fatigue crack propagation life of welded joints. Dissimilar mechanical properties of base, weld and heat-affected zone metals also influence the fatigue crack propagation life.