Genetic algorithms for inverse cathodic protection problems

Abstract

Cathodic protection (CP) is a corrosion prevention technique which uses electrochemical properties of metals to insure that the structure to be protected becomes the cathode of an electrolytic cell. The technique is commonly used for protecting metallic structures placed in aggressive environments, e.g. ship hulls, offshore structures and underground pipelines. Mathematical models of CP problems require appropriate boundary conditions given by a polarization curve, which is a non-linear relationship between the electrochemical potential and current density. However, information on the polarization curve is not always available and strongly depends on the time history of the system. Another important problem in corrosion engineering is the identification of coating holidays, i.e. parts of the structure which have lost their protective coating and became anodic and prone to strong localized corrosion. The purpose of this paper is to present a boundary element methodology coupled to genetic algorithms for inverse problems in corrosion engineering. The problems studied include the identification of parameters characterizing the polarization curve, the identification of coating holidays and the optimization of anode positioning and their impressed current. Several results of applications are discussed, including CP studies of practical three-dimensional engineering problems.