Geometrical effects of notches to the cycles of fatigue crack initiation and crack propagation

The construction of a mechanical engineering structure often contains changes of cross-sections, notches. The geometry of notches affects both on the phase of fatigue crack initiation and propagation. These structures often contain welded joints, too. The production of the joints without any continuity flaws is realisable only theoretically and the flaws can be the places of the crack initiation and the propagation. These causes give the motivation of the investigation of geometrical effects of notches for the number of cycles of fatigue crack initiation and crack propagation in the case of welded joints. The paper demonstrates the obtained results and their valuations.