Font Size: 

The integral approach is considered to be the proper one to be used for formulation of multi-axial fatigue criteria. The results of experimental verification of belonging to this group Zenner criterion confirm its efficiency in for non-proportional loads. Thanks to application of a generalized fatigue parameter, this criterion is useful for different types of proportional loads and for various materials. However, for non-proportional loads of high non-proportionality degree, the fatigue estimation error often exceeds scatter band 3. In this paper a proposal has been presented concerning modification of Zenner criterion. It involves introduction of a load non-proportionality measure by means of the MCE method.