Modeling Aircraft Galvanic Stress Controlled By Kinetic Limitations

Thursday, October 15, 2015: 08:20
102-A (Phoenix Convention Center)
J. S. Lee (Naval Research Laboratory)
Repair and replacement of structural components due to galvanic corrosion degradation are high cost drivers in aircraft maintenance. Sea-based aviation platforms experience one of the most corrosive operational environments in the Navy.  Platform designs are not typically optimized for corrosion performance due to poor materials selection, lack of isolation of dissimilar materials, and geometric features which enhance susceptibility to corrosion. A technological gap exists in the capability of lifetime predictions for galvanically coupled airframe components. While traditional galvanic corrosion models evaluate galvanic stress based on the thermodynamic differences in potential, environmentally-dependent kinetic surface reactions are often not taken into account.  The models that do consider kinetic influences use theoretical estimates with little relevance to the exposure environment. A computational model has been designed to develop a basic understanding of the kinetic mechanisms controlling galvanic stress for different aerospace alloy combinations exposed in marine environments. The novelty of the model is that electrochemical boundary conditions are a function of electrolyte chemistry. Regression analysis of the critical boundary condition factors will be used to examine the effects of kinetic limitation on galvanic stress damage.