Evaluation of multiaxial high-cycle fatigue criteria under proportional loading for S355 steel

Multiaxial stresses are usually present in engineering structures and are often associated to multiaxial fatigue failures. However, multiaxial fatigue is an open topic, full of questions and different points of view. Therefore, an experimental campaign of uniaxial and multiaxial fatigue tests under proportional loading was conducted aiming at evaluating the multiaxial fatigue behaviour of S355 structural steel in the high-cycle fatigue regime. Five different multiaxial models were used and evaluated, namely the Sines, Findley, McDiarmid, Dang Van and Susmel-MWCM. Each of them was applied to experimental data and the mean fatigue curves obtained from it were evaluated and compared. The coefficients present in each model definition were studied and determined through different methods. The Dang Van’s multiscale approach and Susmel model showed great accuracy in the description of the fatigue behaviour of the S355 steel, providing the best correlation of the uniaxial and multiaxial experimental data.