A reliability model to balance the beneficial and adverse impacts of maintenance

This paper describes a component-level maintenance model to evaluate the impact of maintenance on a component`s performance. The model uses a Markov approach to include both the beneficial and adverse effects of maintenance which considers the degraded state of a component, in addition to its operational state and failed state. The beneficial effect of maintenance relates to its effect in improving the reliability of the component, i.e., maintenance corrects degradations before failures occur. The adverse effects of maintenance includes maintenance downtimes and maintenance-related errors, which traditionally are included in component-level models of a probabilistic risk assessment. The authors present example applications of the model and discuss uses of the results obtained from such an analysis. The model will provide a quantitative basis for making decisions on maintenance to achieve the level of component performance desired.