Consideration of fretting fatigue in the calculation concept of the FVA guideline

Abstract Fretting fatigue is still a major challenge in the strength assessment of components with contact. The calculation method according to Vidner [1], which is based on the FKM guideline with local stresses [2], enables the engineer to assess the reduction in strength due to fretting loading for the most critical tribological load. This is realised by empirically determined fretting factors, which are used in the fatigue analysis. Hauschild [3] and Knabner [4, 5] have determined the experimental data for the material groups steel, aluminium and cast iron and implemented the respective fretting fatigue factors in the FKM guideline [2] followed by a validation on connecting rods. In the case of multi-axial stress states—as usually occur with fretting fatigue—the FKM guideline uses the criteria according to von Mises or Rankine (or mixed forms thereof, depending on the ductility of the material). The disadvantage here is that only proportional, i.e. simply superimposed, stress states can be correctly assessed. In the case of shaft-hub connections, however, non-proportional stress states can occur—also due to superimposed loads from bending and torsion. The newly designed FVA guideline [6] offers a solution with its modular structure and the individually selectable equivalent stress hypothesis. Therefore, the work presented here will transfer the fretting factors for steel (from the FKM guideline) to the FVA guideline.