A Stress-based Approach for Evaluating the High-cycle Fatigue Resistance under Multiaxial Loading

摘要

This paper presents an efficient approach for evaluating the high-cycle fatigue resistance of components under general multiaxial fatigue loadings. The non-proportional loading effect is studied and a new efficient approach is proposed for evaluating the effective shear stress amplitude throughout a complex loading cycle. The idea of this approach is to construct a minimum circumscribed ellipse enclosing the loading path in the transformed deviatoric stress space. The new definition of the effective shear stress amplitude is the root mean square of the major semi-axis and the minor semi-axis of the minimum circumscribed ellipse, to take into account the out-of-phase loading effects. With this new approach, the stress invariant-based multiaxial fatigue criteria (such as the Sines or Crossland criteria) can be applied with improved accuracy for fatigue evaluation under out-of-phase multiaxial loading. Test results collected from the literature, which include complex stress histories with different waveforms, frequencies, out-of-phase angles and mean stresses, were used to validate the approach here proposed.