High and low cycle fatigue life estimation of welding steel under constant amplitude loading: Analysis of different multiaxial damage models and in-phase and out-of-phase loading effects

The objective of the present work is to estimate the high and low cycle fatigue life of a type of welding steel used for construction (S355 J2 according to UNE EN 10025-2: 2006), subject to in-phase and out-of-phase multiaxial loading, by means of different classical multiaxial fatigue damage models. A complete cyclic characterization of the material is obtained, including new experimental ε–N fatigue curves both for tension–compression and torsion loading, hitherto unavailable in the literature. A detailed discussion of the morphology and microstructure of the obtained specimen fractures is also provided as well as a proposal is made for an existent damage model to be used to deal with the kind of material studied under multiaxial load situations. The work has been developed using the experimental equipment and procedures available at the Instituto Tecnológico de Aragón (Zaragoza – Spain).