Application of different fatigue strength criteria on shot peened notched parts. Part 2: nominal and local stress approaches

摘要

Fatigue life prediction for notched components is an essential step within the design process of machines. In the past years different fatigue criteria have been applied for fatigue behaviour assessment of notched components subjected to shot peening treatment. However, due to complexity of the phenomenon, still an agreed set of standard methods for predicting fatigue endurance of shot peened notched parts is not available. In this work a series of recognized fatigue strength evaluation methods are applied on two notched shot peened specimens under different fatigue loading. After having considered the approaches based on fracture mechanics (see Part 1), now the local stress methods and the FKM guideline (which includes both a nominal stress approach and a local stress one) are considered. The results allow evidencing the criteria able to better consider the effect of SP and to underline the critical points related to the application of the mentioned criteria to shot peened parts. In this regard the FKM guideline and the approach based on critical distance theory are found to provide more accurate results.