On the combination of a critical plane-based multiaxial fatigue criterion with the critical distance theory for predicting the fretting fatigue strength of press-fitted axles

Two numerical methodologies, developed based on the original Modified Wo center dot hler Curve Method (O-MWCM) and its further modified version (FM-MWCM), were used to predict the fretting fatigue strength of press-fitted axles. Three experimental fretting fatigue strengths, defined by different fatigue failure criteria, were then used to validate both methodologies. The effect of geometric shapes on fatigue strength was also studied using the two methodologies. Finally, based on the obtained results, a more appropriate one for press-fitted axles was determined. The investigation results revealed that, in contrast to the O-MWCM, the FM-MWCM neglected the inhibitory effect of the negative normal stress on the critical plane on crack initiation. The methodology developed based on the FM-MWCM could reasonably predict the fretting fatigue strength of press-fitted axles with fillet radii at the contact edges, and accurately predict the evolution trend of the fretting fatigue strength with the fillet radius, diameter ratio, and hub overlap. From an engineering viewpoint, this methodology can serve as an auxiliary tool to optimise geometric shapes of press-fitted parts. When using the methodology to predict the fretting fatigue strength, it is essential to clearly know the fretting fatigue failure criterion corresponding to the prediction results. A mismatch between the failure criterion of the prediction results and the criterion used for defining failure in designing press-fitted axles may result in severe consequences.