Incremental fatigue damage modeling of 7050-T7 aluminum alloy at stress-raisers

The Ottosen-Stenstrom-Ristinmaa (OSR) incremental fatigue damage model, based on an moving endurance surface centered around a backstress, is adapted for high-cycle fatigue at stress-raisers in AA7050-T7 specimens. Fatigue experiments are carried out for circumferentially-notched, axisymmetric specimens subjected to constant-amplitude (CA) load. The OSR model parameters are fitted to CA fatigue data, showing fair agreement for one set of model parameters across different stress ratios, stress concentration factors, uniaxial stress and biaxial stress. To demonstrate predictive capability, the fatigue life is integrated for an aircraft load spectrum (TWIST), and compared with experimental fatigue life data for holeplate specimens in the literature.

Automated summary

The study adapts the OSR incremental fatigue damage model for high-cycle fatigue in specimens with stress-raisers in AA7050-T7, showing good agreement across different conditions. By integrating fatigue life for an aircraft load spectrum, the predictive capability of the model is demonstrated.