Three-point bending performance of carbon steel with random pitting corrosion in marine environments

Carbon steel is prone to corrosion in marine environments. This significantly deteriorates its bending mechanical properties and has the potential to compromise the long-term serviceability, safety and reliability of marine infrastructure. A combined experimental and numerical simulation approach was employed to investigate the degradation mechanisms affecting the bending performance of carbon steel in marine environments. This approach was used to systematically examine the corrosion morphology characteristics and the evolution of the three-point bending mechanical properties of corrosion carbon steel. This study was designed to quantitatively analyze the degradation relationship between thickness loss rate and bending performance through tensile tests and three-point bending tests conducted on 42 carbon steel specimens. A three-dimensional numerical simulation of corroded specimens was created based on a random method. The results indicate that: 1) the thickness loss rate of the specimens increased linearly as the exposed time increased. Conversely, the ultimate bending load was found to vary inversely with the loss of thickness. The ultimate bending load decreases by more than 31.9 % when the thickness loss rate reaches 7.9 %. 2) Through comparative analysis between computational and experimental results, an average relative error of merely 6.2 % was observed, confirming the reliability of the finite element analysis method. 3) Corrosion time is also a key factor influencing performance degradation: when corrosion time reaches 300 days and 400 days, the corresponding ultimate bending loads decrease by 41.7 % and 55.6 %, respectively.