Cathodic protection is used to control the corrosion of a metal surface by creating a current flow from the cathodic protection system to the structure. There are two basic methods; Galvanic and Impressed Current. In a galvanic cathodic protection system, the anodes connected to the structure requiring protection have a natural potential that is more negative than the structure’s. When the anodes are connected, a current flows from the anode (which is at a more negative potential) to the structure (which is at a less negative potential) in a DC circuit. OPERA has been used extensively to analyse this type of behaviour, primarily in the marine marketplace for corrosion protection of ships and boats.
- Ship hulls
- Steel in concrete
- Heat Exchangers
- Marine piles and walls
For a typical marine galvanic CP analysis, Opera requires a model of the exterior surface of the vessel including
– Impressed current anodes
– Sacrificial anodes
– Painted and unprotected areas
The volume of sea and sea-bed surrounding vessel meshed with finite elements and material conductivity is specified.
Opera’s results post-processing allows for the interrogation of many useful results, including:
– Potential distribution on vessel, showing the effectiveness of CP system.
– Electric field distribution anywhere in modelled volume of sea and sea-bed
– Current density distribution anywhere in modelled volume of sea and sea-bed
– Resultant magnetic field from currents flowing in sea and sea-bed
Is it possible to perform Cathodic Protection calculations using Finite Element Analysis such as Opera?
causes corrosion. The modified potential distribution then prevents (or at least reduces) corrosion.