Numerical study for reliability assessment of a corroding pipe to flange weld joint over its lifetime

Failure probability of a corroding pipe to flange weld joint over its lifetime was investigated. A numerical model of a corroded weld joint connecting pipe to flange using finite element method was developed, and coupled with usual stress models. The structure material has been characterized experimentally. An empirical mechanical behavior model of the studied structure has been also proposed. Monte Carlo simulations, FORM and SORM methods have been applied for estimating reliability and failure probability under the both effects of corrosion and residual stress. A numerical case with high, moderate and low corrosion rates was conducted to determine the reliability of the welded connection pipe to flange. The founding results are analyzed and discussed for various corrosion rates. The obtaining result shows that the heat affected zone due to the welding process is very sensitive to corrosion effects. Hence, it is necessary to ensuring a rigorous inspection to ovoid human and environmental disasters.