Investigation on the stress concentration effect at the corroded surface achieved by atmospheric exposure test

In this study, the time-dependent stress concentration effects on the corroded surface of a steel structure with deteriorated paint coating were examined to investigate potential fatigue problems and stress concentration levels. Toward this end, atmospheric exposure tests were conducted on carbon steel in different atmospheric environments for four years, and the stress concentration effects on the corroded surface were numerically analyzed based on these tests. The spatial coordinates of the corroded surface were imported using a laser scanning program for finite element (FE) analyses. The experimental tests and numerical analysis showed that the maximum stress occurred at the maximum corroded depth on the corroded surfaces. The stress concentration factor (SCF) under time-dependent atmospheric exposure conditions was ~1.6 for the uniform corroded surface. The SCF of the localized corroded surface sharply increased to ~3.0 in the deeper localized corrosion pit. Therefore, fatigue crack nucleation can develop from the stress concentration of the corroded surface with localized corrosion where the paint coating of the structural steel member has deteriorated.