Monopile with Dissolving Sacrificial Anodes

Application ID: 36071

A monopile foundation is a large-diameter structural element that can be used to support structures like offshore wind turbines. This application exemplifies how the cathodic protection of a monopile decreases over time as the sacrificial anodes dissolve. The model can be used to evaluate secondary current distribution electrode kinetics on the protected steel structure by taking into account the simultaneous electrochemical reactions that lead to metal dissolution and oxygen reduction (mixed potential).

The monopile geometry consists of an upper component with a coated steel surface and a lower uncoated steel pipe. It is also surrounded by either seawater or mud, with differing Tafel expression reaction kinetics used for these different environments. The tutorial model is solved using a time-dependent study for a time period of 12 years. Two cases are investigated: when the whole monopile is grounded, and when the transition piece is grounded and the lower pipe is connected to the transition piece through a lumped resistance.

The model also uses the new customized Sacrificial Edge Anode subnode for modeling slender sacrificial anodes along geometric edges, which is now available in the Secondary Current Distribution interface. The subnode enables you to model the changing cathodic protection properties of the anodes as they dissolve in time-dependent simulations.

This model example illustrates applications of this type that would nominally be built using the following products: