Session: 02-09-01 Reliability of Moorings & Risers

Submission Number: 179546

A Reliability-Based Inspection Framework for Digital Twins of Mooring Lines of Floating Offshore Structures 

This paper presents an innovative reliability-based inspection framework for the mooring lines of floating offshore units, which optimizes inspection scheduling in real time using operational data provided by a digital twin of the unit. Conventional inspection plans rely on fixed periodic inspections and conservative fatigue assumptions, often neglecting actual operational conditions and observed corrosion development. In the proposed framework, a digital twin of the floating unit provides real time vessel motions, which are post-processed to estimate short-term fatigue damage. A hybrid time-frequency domain approach incorporates dynamic effects into the responses and efficiently estimates the stress time series required for fatigue damage estimation. The accumulated fatigue damage is then used in a probabilistic reliability model that continuously updates the mooring line’s failure probability, explicitly accounting for mean loads and corrosion grades. Inspections are not tied to fixed schedules but are suggested when the reliability index reaches a critical threshold. As new inspection findings become available, the model is updated, and future inspection intervals are recalculated. This adaptive methodology allows inspections to be postponed under favorable conditions or anticipated in cases of faster degradation. By linking inspection planning to the actual unit condition rather than relying on conservative assumptions, the framework enables more efficient use of inspection resources while maintaining control over mooring integrity risks.

Presenting Author: Fellipe Araujo Gomes Federal University of Rio de Janeiro

Presenting Author Biography: Fellipe A Gomes holds a bachelor’s degree in Civil Engineering from the Federal University of Sergipe (UFS) and a master’s degree in Civil Engineering from COPPE/UFRJ. He is currently pursuing his Ph.D. at COPPE/UFRJ, focusing on the design and fatigue assessment of prestressed concrete floating platforms for offshore wind applications. As a researcher at LACEO/COPPE/UFRJ, his work centers on reliability-based inspection and life-extension methodologies for mooring systems, integrating structural reliability, fatigue analysis, and digital-twin frameworks for offshore assets.

Authors:

Fellipe Araujo Gomes Federal University of Rio de Janeiro
Gabriela Alves Estrela Federal University of Rio de Janeiro
Marina Leivas Simão Federal University of Rio de Janeiro
Paulo Maurício Videiro Federal University of Rio de Janeiro
Luis Volnei Sudati Sagrilo Federal University of Rio de Janeiro
Bai-Qiao Chen University of Lisbon
Mauro Costa De Oliveira Petrobras
Rodrigo Augusto Barreira Petrobras