Effects of corrosion damage on mechanical properties and stress state evolution in corroded steel structures

Purpose The purpose of this study is to investigate the effects of pitting corrosion on the mechanical properties and local stress states of steel plates. Design/methodology/approach Tensile tests were performed on specimens subjected accelerated corrosion to investigate relationships between mechanical properties and pitting parameters. The evolution of corrosion-induced stress state was analyzed using 3D reverse reconstruction models. Furthermore, the correlations among stress triaxiality (η), Lode angle parameter (θ-), pit depth (d) and the width-to-depth ratio (Rw/d) were systematically evaluated. Findings The results showed that the degradation of mechanical properties exhibits significant stochasticity. Tensile strength was governed primarily by critical corrosion pits, while ductility was more affected by residual thickness. Corrosion damage significantly altered stress triaxiality and Lode angle parameter, especially under complex stress states. These alterations accelerated localized fracture initiation. Based on these results, a novel predictive model was developed that couples stress state parameters with pit morphology to accurately estimate η and θ- across a wide range of stress states. Originality/value This model accurately predicts the stress state of corroded steel under complex loading conditions. It provides critical insights for assessing high-risk regions in corroded steel and facilitates the development of corrosion-modified fracture models.