Degradation-based maintenance or mean residual life-based maintenance?

Abstract : This paper provides a methodology to assess the efficiency of two well-known reliability indicators: degradation level and mean residual life (MRL) for the condition-based maintenance (CBM) decision-making. Two simple inspection/replacement policies corresponding to the considered reliability indicators are developed and applied for two kinds of deterioration/failure models. In the first model, only the degradation causes system failures, while in the second one, failures are due to the competing causes of degradation and shocks. Comparisons on the optimal maintenance cost rate of both maintenance policies are done under different situations of maintenance costs. The numerical results show that the MRL-based maintenance can be considered as a general approach of degradation-based maintenance, and in the case of the more complex deterioration/failure model, making a preventive maintenance decision based on the MRL can lead to a reduced maintenance cost.