Influence of data size on the reliability assessment of creep life of grade 91 steel

摘要

Influence of data size on a reliability assessment of the long-term creep life of Grade 91 steel was investigated for two different sets of large body of creep-rupture data comprising 690 (Set-1) and 1072 (Set-2) data points. The Z-parameter on the Larson-Miller parameter of creep rupture data supported a normal distribution well. Based on the normal distribution, the reliability of the predicted creep life for the two data sets was assessed to obtain variations in reliability owing to fluctuations in the service conditions and the dispersion of the creep data using a service condition-creep rupture property interference (SCRI) model. A large number of random variables for Z-parameter were generated using Monte-Carlo simulation. A reliability assessment for the two data sizes under specific service conditions has been comparatively demonstrated. It was found that the size of the creep-rupture data influenced the reliability of the creep life prediction.