Comparison of different one-parameter damage laws and local stress-strain approaches in multiaxial fatigue life assessment of notched components

Abstract

This paper aims to compare the predictive capabilities of different one-parameter damage laws and local stress-strain approaches to assess the fatigue lifetime in notched components subjected to proportional bending-torsion loading. The tested fatigue damage parameters are defined using well-known stress-based, strain-based, SWT-based and energy-based relationships. Multiaxial cyclic plasticity at the notch-controlled process zone is accounted for within a 3D-FE linear-elastic framework using three local stress-strain approaches, namely Neuber’s rule, equivalent strain energy density rule (ESED) and the modified ESED rule. Regarding the local stress-strain approaches, irrespective of the fatigue damage parameter, Neuber’s rule always led to more conservative results, and the modified ESED rule resulted in slightly better fatigue life predictions when compared to the original ESED rule. As far as the fatigue damage parameters are concerned, energy-based models were more accurate, irrespective of the local stress-strain approach.