The impact of corrosion-stress interactions on the topological features and ultimate strength of large-scale steel structures. (December 2020)

• Record Type: Journal Article
• Authors: Ilman, Eko C.; Wang, Yikun; Wharton, Julian A.; Sobey, Adam J.
• Is Part Of: Thin-walled structures. Volume 157(2020)
• Publication Date: 2020-12
• Subjects: Steel -- Finite element method -- Grillage -- Marine corrosion -- Ships and offshore structures -- Mechano-electrochemistry; Thin-walled structures -- Periodicals; 690.1
• DOI: 10.1016/j.tws.2020.107104
• Languages: English
• ISSNs: 0263-8231

Abstract

Abstract: Aged marine structural analysis often relies on simplified corrosion modelling. Empirical or statistical methods are used to predict a uniform thickness reduction over time. Although convenient, this approach cannot incorporate the corrosion evolution or the rough surfaces in the damaged area. This is fundamentally due to the lack of representation of the underlying corrosion mechanisms in service environments. To better understand how structural response changes based on corrosion under service loads, this paper presents a series of finite element analyses which consider the coupling relationship between the surface mechanical stresses and the resulting change of corrosion rate. The coupling provide complex corrosion-stress interaction depending on the experimental datasets. The quantification of this interaction is based on in situ experimental measurements of corrosion kinetics at different stress levels. The simulations show the stress effect results in the generation of more realistic corrosion patterns on the structural surface, based on a two-bay/two-span large-scale panel model subject to uniaxial compression. In addition, the incorporation of corrosion experiments allows the modelling of corrosion evolution based on physical observations instead of empirical assumptions. The irregular surface damage leads to a change in structural buckling mode, and up to 8% reduction in ultimate strength compared to models without considering the stress effect. Highlights: Incorporation of the stress-corrosion coupling/interactions in FEA structural analysis. Comparison with traditional structural modelling with corrosion damage. Predictions of corrosion evolution and surface damage based on physical measurements. Significant changes in structural buckling mode due to newly predicted corrosion topology. Parametric studies assessing influences of scantling, imperfection & corrosion location.