Ultimate Strength of FPSO Stiffened Panels With Pitting Corrosion

Abstract Corrosion in cargo tanks on FPSO platforms is a reality, due to it operates in hostile environmental conditions. Furthermore, their internal structures, often unprotected, are exposed to corrosive gases, sea water, oil and derivatives, which contribute to corrosion. Pitting corrosion manifests as a concentrated and expedited deterioration of metal as a consequence of the deterioration of the passive protective film on the metal surface. This paper aims to investigate the impact of pitting corrosion parameters on the ultimate strength of FPSO stiffened panels, using authentic pitting corrosion data obtained from an FPSO platform operating in the waters of Brazil. Numerical models of FPSO platform bottom panels from a cargo tank were developed using a finite element program. A code was developed to generate pits featuring diverse geometries, locations, distinct patterns and intensities. These pits were inserted to systematically assess their influence structural. A simulation methodology was proposed and implemented based on actual pitting corrosion measurement. The proposed method proved to be adequate for analyzing the ultimate strength of corroded panels and can be used in other panels, utilizing measurements carried out in loco. The results showed the negative influence of the pitting corrosion parameters analyzed on the ultimate strength of the stiffened panels.