Digital twin-enhanced risk-based inspection for offshore structures considering fatigue cracks

Inspection is vital for managing the integrity of offshore structures, allowing for detecting and repairing issues like fatigue cracks to ensure their fitness-for-service. Optimising the scheduling of these inspections, which can be costly, is crucial, making risk-based inspection practices particularly relevant. Practical risk assessments depend on a thorough understanding of operational profiles to predict structural performance accurately. This paper presents an optimisation framework incorporating digital twin technology to enhance monitoring and update fatigue load profiles. Using a probabilistic fracture mechanics model, the framework simulates fatigue crack growth and assesses remaining life through a reliability index. It employs bi-objective optimisation to minimise costs while maximising structural reliability, ultimately determining the optimal inspection plan aided by multi-criteria decision analysis.