Abstract
A practical approach for the reliability evaluation of structure under corrosive environment has been proposed and applied to an oil storage tank as an example. The failure of an oil tank was classified into two modes. One is fatigue fracture caused by the thickness reduction of bottom plate by uniform corrosion and the other is the leakage of contents from the pits caused by localized corrosion. For the evaluation of uniform corrosion, corrosion rate has been treated as a random variable and maximum stress distribution has been calculated by Monte-Carlo simulation. On the other hand, in case of localized corrosion, maximum pit depth has been evaluated by the simulation of pit growth. As a result, the effect of the leakage by localized corrosion becomes large when the uniform corrosion rate is comparatively slow. However, the risk caused by fatigue fracture increased rapidly when the uniform corrosion rate became large.
