Reliability assessment of cracked pipes subjected to creep-fatigue loading

•The contribution of creep and fatigue to the total crack growth has been evaluated in deterministic calculations.•Creep-fatigue reliability analysis have been performed on defective pipes.•Various parameters have been considered as random variables.•Reliability of the cracked pipes has been determined at different operation times.•The effects of reducing the scattering of the random variables have been examined.•Sensitivity analysis has been performed to investigate the importance of different random variables.•Reliability analyses have been conducted using different reliability methods. The reliability analysis of defective pipes, which operate under creep-fatigue loading conditions has been studied. An austenitic stainless steel pipe containing an axially external semi-elliptical surface crack, subjected to variable internal pressure at elevated temperature has been considered as the benchmark problem. Different parameters in material behavior, geometry parameters, and operational condition have been assumed as random variables in the probabilistic assessments. The reliability of the cracked pipes have been evaluated at various operation times, using different reliability methods. Sensitivity analyses have been conducted to investigate the importance measure of the random variables involved in the problem. Moreover, the effects of reducing the scattering of the random variables on the variations of the reliability index, β, has been examined.