Multiaxial fatigue assessment of S355 steel in the high-cycle region by using Susmel’s criterion

Multiaxial fatigue is frequently present on engineering structures and is the cause of many mechanical failures. However, multiaxial fatigue analysis is full of questions and different points of view. Thus, throughout this study, Susmel’s criterion, a recent multiaxial fatigue damage model also known as the Modified Wöhler Curve Method, is presented, explained and assessed. Experimental data of axial, torsional and proportional (axial+torsional) fatigue tests conducted on S355 structural steel and under different stress ratios were analysed and evaluated according to this model. Mean fatigue design curves for each loading condition were obtained and plotted in the high cycle fatigue region. Finally, the ability of Susmel’s criterion to assess the multiaxial fatigue behaviour of S355 steel in the high cycle region was evaluated by determining the error index between the theoretically estimated and the experimental fatigue damage. Susmel’s model was found to be adequate to describe the fatigue behaviour of the steel under study in high cycle region.