Clustering condition-based maintenance for a multi-unit system with aperiodic inspections

Condition-Based Maintenance (CBM) is a predictive maintenance strategy, which bases the maintenance scheduling on condition measurements of the components. In this paper, we continue work on the CBM optimization approach proposed by Castanier, B., A. Grall & C. Bérenguer (2005). A condition-based maintenance policy with non-periodic inspections for a two-unit series system. Reliability Engineering & System Safety 87(1), 109–120. Their approach is advanced, compared to those proposed by others, in that it optimizes both the inspection moments and the condition thresholds (on which the planning of maintenance actions is based) simultaneously. It considers a discrete-time system with two machines that operate in series, where the objective is to minimize the long-run average maintenance cost per time unit. We analyze an adapted version of their system where two machines operate in parallel rather than in series, and provide new insights on CBM for such systems. Furthermore, an extensive comparison to other (classical) maintenance policies, such as failure-based maintenance, block replacement, and condition-based maintenance with periodic inspections, is included