Modified model for evaluating fatigue behaviors and lifetimes of notched aluminum-alloys at temperatures of 25 °C and −70 °C

A new S-N-R surface model accounting for the stress ratio effect is proposed to depict fatigue behavior, and a modified damage accumulative rule considering the load interaction is presented to assess fatigue lifetimes under random spectra loading. Fatigue tests were performed on notched aluminum-alloys 2524-T3 and 7050-T7451 subjected to constant amplitude and random spectra loading at 25 °C room and −70 °C cryogenic temperatures, and the load-environment interaction and load interaction mechanisms were deduced from fractographic analysis. The new model shows good correlation with experimental results.