Fatigue strength degradation of metals in corrosive environments

Fatigue strength degradation of corroded structural details: A formula for S‐N curve

“…The fatigue endurance/strength of corroded material reaches a threshold after a certain period of exposure to corrosive environment. Fatigue test results of steel specimens show that the difference between fatigue lives in corrosive and non‐corrosive environments LCF region is negligible and a significant larger difference is observed in VHCF region …”

“…The modified corroded curve has the same slope with the air curve until 10 7 cycles. This violates CF behaviour of steels, which has negligible difference between fatigue lives in corrosive and non‐corrosive environments in the low‐cycle fatigue (LCF) region when compared to VHCF region …”

“…Corrosion commonly takes place in the splash zone area of offshore structures as the coating in this area disappears a few years after installation . Recent collapses of steel bridges due to corrosion are reported and some examples are the Silver Bridge in 1967, the Mianus River Bridge in 1990 and the Minnesota Bridge in 2007 . Though many bridges are located onshore, de‐icing salt may simulate marine environment to the bridges in snowy regions .…”

“…Fatigue crack propagation life is determined by fracture mechanics approach. Accurate determination of modified corrosion‐fatigue stress intensity threshold and the critical length has been reported as challenging and difficult . Therefore, limited amount of published works is found in the area of fatigue notch factor due to pitting corrosion .…”

“…Due to mentioned complexities of the model and uncertainties of the model parameters, few applications are reported. A stress‐life fatigue strength curve for corroded material is recently published . The proposed curve depends on corrosion parameter, σ ∞,cor, which should be determined by CF tests in very high cycle fatigue (VHCF) region in relevant corrosive media.…”