Reliability of a Flexible Subsea Riser under Repetitive Random Loads and a Power Law Degraded Capacity

We discuss a model that considers random loads (ship displacements, subsea currents, riser weight and fluid weight) occurring on subsea flexible risers and a degrading capacity with an initial random capacity. The number of occurrences of repetitive loads follows Poisson distributions. All loads and riser initial capacity are modeled by uniform distributions to allow analytical solutions. The degradation model is a power law.The riser reliability is the product of all contributions. Scarce field and literature data has been gathered for the initial evaluations. The riser time-dependent reliability is useful as a means for setting inspection policies.