Incorporation of high‐altitude environmental effects in the linear elastic fracture mechanics‐based modeling of aluminum alloy 7075

Airframe structural components experience coupled load–environment spectra that are currently not captured in traditional damage‐tolerant management approaches. The effect of incorporating fatigue crack growth kinetics relevant to high‐altitude flight environments into LEFM‐based predictions of fatigue progression for aluminum alloy 7075‐T651 was quantitatively assessed for a variety of load–environment spectra using AFGROW. The results of this study demonstrated that in all conditions, the incorporation of high‐altitude‐relevant growth kinetics enhanced the fatigue life predictions. However, the magnitude of the impact on the overall life is dependent upon the subtleties of the coupled load–environment spectrum, despite the fact that environmental effects are most potent in the near‐threshold regime of the da/dN versus ΔK relationship. The potential impact to the structural integrity management community is discussed, and remaining challenges and opportunities are identified. Highlights Applying low water vapor pressure fatigue growth rates extended fatigue life in LEFM modeling. When applied to in‐service loading spectrum for aerospace applications, this extension was maintained. Subtleties with environment loading and fatigue life were investigated.