Stress evolution in multilayer polymer coating under thermal and pressure loading applied to the pipeline structure

Highlights: • Residual stresses in the coating are between 4 and 9 MPa due to the process. • Good agreement between industrial measurements and numerical model. • Critical interface of the assembly is the Steel/FBE. • Residual stress can explained the disbanding especially in humid environment. Pipelines must have good mechanical properties during their service life. To improve this lifetime, a protection against corrosion is applied on the steel cylinder by coupling a passive coating with an active cathodic protection. Otherwise, it is well known that the presence of internal stresses in organic coatings is a current phenomenon which can result in the loss of adhesion. These phenomena can be critical for safety and lead to expensive maintenance operations. In order to identify areas of overstress and estimate the values reached in the pipeline, and especially in its coating, the development of numerical models appears relevant. The models show that significant stresses are present in the coating and at the different interfaces during the pipeline operation. Their values change with the different loading cases which can be encountered on the transportation network. From these results, the stress is essentially concentrated in the steel/coating interface with a maximal value lower than 10 MPa.