A Theoretical Investigation of the Mechanics of Structural Failure in Single-Hull Tankers Under Corrosion-Accelerated Fatigue in Tropical Marine Environments

The interaction between electrochemical corrosion and cyclic fatigue loading in the structural members of single-hull tankers creates damage accumulation mechanisms that are not fully captured by established fatigue assessment standards developed for temperate maritime environments. This study conducts a theoretical investigation into the mechanics of corrosion-fatigue structural failure in single-hull tankers operating in tropical marine environments, with specific application to vessel types prevalent in Nigerian coastal tanker trade. The research employs an analytical mechanics methodology combining theoretical formulation of corrosion-fatigue crack propagation models incorporating tropical environmental parameters, finite element structural modelling of representative tanker structural configurations, and experimental validation using accelerated corrosion-fatigue testing of steel specimens in simulated tropical seawater conditions. The theoretical contribution of the study lies in the development of an original corrosion-fatigue damage accumulation model that incorporates temperature-dependent corrosion rate functions calibrated to the Gulf of Guinea marine environment, the inhibiting effect of cathodic protection on crack tip electrochemistry, and the statistical distribution of weld defect populations in Nigerian shipyard fabrication. The model is applied to predict residual structural life for selected structural configurations and is validated against documented structural survey findings from five coastal tankers. The study advances the structural mechanics literature by providing a theoretically grounded and environmentally specific corrosion-fatigue model. Keywords: corrosion-fatigue, single-hull tanker, structural failure mechanics, tropical marine environment, finite element analysis