Assessment of the Effect of Predictive Maintenance on the System Reliability

Abstract

In this work, we assess the effect of predictive maintenance on the reliability of repairable systems. In reparable systems, the reliability assessment considering corrective and preventive maintenance is well defined, but not considering predictive one. The effect of predictive maintenance is taken into account through a finite probability that the system is found in degraded condition. If the predictive maintenance evidences the degradation, then the repair is carried out. All the repairs are considered perfects, which means that the system is restored to an as-good-as-new condition each time the repair is carried out. The measure of system reliability under predictive maintenance is found to be between that of a maintenance-free strategy and preventive maintenance. The effect on the system reliability depends on the value of the probability that the system is found in degraded condition. We propose an expression for the reliability that is convenient when values of such probability are less than 15%. By using the proposed expression, one can estimate how much improvement in reliability any system gains by the predictive maintenance.