New models for prediction of high cycle fatigue failure based on highly loaded regions

The stress gradient and the structural size are known to be very important factors affecting the fatigue life of metallic mechanical components. For multiaxial stress conditions, a relevant criterion must be used to account for both these effects as well as the history of a non-homogeneous stress state. The new probabilistic HCF models in this work fulfill these requirements. A stress field resulting from rotating bending is analyzed. Also, the well-known weakest link model has be compared to the new proposed HCF models based on the concept of the highly loaded regions. The new models take the highly loaded regions (volume, area) and the stress gradient effect into account. These models show significant improvement of failure probability prediction capability compared to the weakest link integral.