Marine structural integrity subject to mechano-electrochemical induced corrosion

摘要

Carbon steel marine platforms, including ships and offshore structures, are at high risk of corrosion due to the combination of aggressive seawater environment, corrosive cargoes and constantly changing loading conditions. In particular, the combined influence of mechanical and electrochemical effects (which is often termed mechano-electrochemistry) has gained increasing attention over the last decade. Although various experiments, along with theoretical/empirical expressions, have been proposed to establish the relationship between stress/strain and the corrosion behavior, there are few in situ measurements of corrosion and the mechanical properties. Moreover, such corrosion mechanisms have not been incorporated for large scale ship or offshore structural members. This work has developed an experimental protocol including in situ potentiostat and quasi-static tensile tests to provide an improved understanding of the corrosion behavior of UNS G10210 steel at different stress levels. A novel local-global finite element method has been proposed to model a steel plate at a ship compartment scale under uniaxial quasi-static tensile/compressive loading. The stress distributions together with the experimental measurements were utilized to simulate a local mechano-electrochemical corrosion process and predict the stress-induced corrosion rate change. The modeling results demonstrate a more realistic approach to estimate marine structural integrity considering stress-induced localized corrosion.