Review of fatigue strength assessment of nonwelded and welded structures based on local parameters

The basic types of the approaches of fatigue strength and service life assessment based on local stress and strain parameters are at first described for nonwelded structures: fatigue phenomena, influence parameters, objectives of the assessment, global and local approaches and historical development. The nominal stress approach, structural stress approach, notch root approach and fracture mechanics approach are reviewed and set into comparison. The peculiarities of welded structures are emphasized: inhomogeneous material, welding residual stresses and geometrical characteristics. The variants of the local approaches mentioned above which are applied to welded structures are specified together with relevant conclusions.