DFR method based on Gerber model under corrosion conditions

In order to study the influence of the equal-life curve models on DFR, the fitting accuracies of Gerber model and Goodman model for high-cycle fatigue data were compared with six typical aviation materials．The formula of DFR based on Gerber model and the expression of corrosion conversion coefficient <i>C</i>_C were derived， pre-corrosion fatigue tests for 0 h, 6 h, 12 h, 24 h, 36 h, and 72 h of 2024-T3 aluminum alloy (surface anodizing) were carried out，and the fatigue fracture of pre-corrosion for 72 hours was analyzed. The results show that Goodman model is suitable for brittle materials while Gerber model is suitable for ductile materials. As the pre-corrosion time increases, the DFR of 2024-T3 aluminum alloy decreases．The DFR based on Gerber model are 84.251 MPa, 84.721 MPa, 79.683 MPa, 80.745 MPa, 77.026 MPa and 74.996 MPa respectively, and the <i>C</i>_C is 1.006, 0.946, 0.958, 0.914 and 0.890，the fitting curve of the DFR with the pre-corrosion time is $ DFR=84.251{\left[ {\lg \left( {t + 10} \right)} \right]^{ - 0.15578}}$. It is found that when <i>N</i>_95/95 &gt; 10⁵, the DFR method based on Gerber model can give full play to the fatigue performance of ductile materials．Corrosion pits produced by pre-corrosion and inclusions in materials can accelerate the formation and expansion of fatigue cracks, but DFR of the anodized specimens is decreased in a corrosive environment compared with the bare materials.