The True Digital Twin Concept for Fatigue Re-Assessment of Marine Structures

The paper presents a true digital twin concept, which is a general and novel methodology that significantly improves the fatigue prediction models of existing marine structures. The actual structural condition of existing marine platforms can often change after several years in operation due to degradation mechanisms and/or other structural changes. It is within this context, the true digital twin concept has been developed and the general idea is to create a coupling between the digital twin and measurements. The measurements are performed by Structural Health Monitoring Systems (SHMS). This coupling facilitates a direct performance evaluation of the digital twin against measurements and most importantly creates the basis for improving the performance of the digital twin to accurately capture the actual condition of the structure, and thus become a true digital twin. The full concept of creating a true digital twin encompass novel advanced analysis methods ranging from linear system identification, expansion processes, Bayesian FE model updating, wave load calibration, quantification of uncertainties from measured data, and Risk- and Reliability Based Inspection Planning (RBI) analysis, [1]. This paper presents the first 3 levels for establishing a true digital twin. The levels are illustrated by 3 case stories.