Experimental Study on Fatigue Behavior of Steel Plates Exposed in Neutral Salt Spray Environment

Fatigue, a critical phenomenon in durability of steel structures, refers to the significant reduction in failure strength compared to yield strength under cyclic loading. This study investigates fatigue behavior of corroded steel subjected to a marine atmosphere. Six steel plates were exposed to accelerated single- or double-sided corrosion in an environmental chamber filled with neutral salt fog. The three-dimensional laser scanning technology was employed for quantification of the surface morphology. Geometric parameters of corrosion pits were extracted by a modified watershed algorithm. The corrosion degree ([Formula: see text] of the steel plates exhibited a positive correlation with the placement angle ([Formula: see text]. The corrosion depth ([Formula: see text] on the top surface and the bottom surface roughly showed a normal distribution and a lognormal distribution, respectively. Statistical analysis demonstrated that the pit depth ([Formula: see text] conformed to multiple distributions such as normal, lognormal, and Gamma distribution, whereas the aspect ratio ([Formula: see text] followed a lognormal distribution. 24 specimens cut from the steel plates were loaded under fatigue. Under single-sided corrosion, the fatigue life of the 0[Formula: see text] specimens was 89.1% longer than that of the 70[Formula: see text] specimens and 55.1% longer than that of the 90[Formula: see text] specimens. Under double-sided corrosion, the fatigue of the 0[Formula: see text] specimens was 27.7% longer than that of the 70[Formula: see text] specimens and 47.0% longer than that of the 90[Formula: see text] specimens. Eventually, a [Formula: see text]–[Formula: see text]–[Formula: see text] curve considering uniform corrosion was established by the IBSIM method.