Simulation of corrosion damage, stress concentration, and fatigue crack growth

Airframe structures regularly operate in environments that allow high levels of corrosion damage, and this damage leads to stress concentrations within the structure and potential development of cracks. Even when only a thin film of electrolyte is present on the structure, this can still lead to an electrical field that causes surface damage.

Computation of this electrical field can be used to identify areas in the airframe structure that are most susceptible to corrosion damage and which, after possible fatigue crack initiation, may lead to structural failure. Corrosion simulation can be used to take account of the properties of the electrolyte as well as the structural materials, to determine the rate of material loss from the structure. Having removed material from the surface (corresponding to corrosion occurring over a given exposure time) the stress concentrations can be evaluated and, if required, cracks can be initiated in each potential problem area, to identify vulnerability to fatigue failure.