Abstract
The offshore environment is inherently corrosive. Consequently, pits may nucleate on exposed steel surfaces. Corrosion pits can be a source of crack initiation when the structure is subject to fatigue loading. The criticality of a corrosion pit with respect to the structural integrity depends on its shape and size and can be quantified using a stress concentration factor (Kt). In this work, a parametric 3D finite element model is developed to perform stress analysis of a pitted plate subjected to uniaxial tensile stress. The model is used for an extensive parameter study in which Kt is determined for various pit configurations. It is demonstrated that each one of the geometric parameters holds a substantial influence on the location of the Most Critical Region (MCR). It is shown that Kt increases as the pit gets narrower. Pits with an elliptical mouth yield higher Kt values when the angle between the load direction and the pit mouth major axis increases. Moreover, Kt increases with the increase in the localized thickness loss which is more pronounced for relatively wider pits. Finally, a regression model is presented for estimating Kt based on the geometric parameters of a pit.
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