Corrosion effect on stress concentration factor in tubular T-joints under axial loading

Abstract

A stress concentration factor (SCF) is used to determine concentrated stress at hotspots for fatigue evaluation of steel fixed offshore platforms. The varying SCF significantly affects the fatigue damage of the hotspot according to the exponential function. Current standards have proposed empirical formulas to determine the SCF at the hotspots of the tubular joints, but it depends on the geometry and some specific limitations. When a tubular joint is corroded, its geometry will be changed, making these limitations unsuitable, especially for the case of non-uniform corrosion. Therefore the formulas are no longer suitable to apply in these cases. This paper uses ABAQUS-based numerical simulation to analyze concentrated stress at saddle and crown points on the chord of non-uniform corroded tubular T-joints under axial loading in some different scenarios. The research indicates that thickness and dimension of corroded zone around the joint intersection substantially influence stress concentration factor and fatigue damage at the mentioned hotspots.