Tracking Reliability and Updating the Overhaul Interval of Engineering Components: Bayesian Approach

The Bayesian approach is commonly used to track the progression of a degradation process and update the reliability of a component. However, there is a wide variety of components in which the failure cannot be attributed to a single well-defined degradation process, and inspection techniques are unable to quantify the state of degradation. For such components, only maintenance records pertaining to the timing of corrective and preventive maintenance are available. This paper focuses on developing an adaptive method to update the reliability and revise the maintenance interval based on the survival history of a component. The paper presents a Weibull mixture model to account for heterogeneity in the lifetime data. The posterior model parameters are estimated through Bayesian updating. The proposed method is illustrated using the lifetime data obtained for a group of level control valves used in steam generators of a Canadian nuclear power plant.

Keywords: Reliability updating, Weibull mixture, Heterogeneous population, Bayesian inference, Markov Chain Monte Carlo (MCMC), Overhaul interval.