Inma Castro

On the Construction of Mean Residual Life for Maintenance Decision-Making

This paper provides a methodology to assess the efficiency of mean residual life (MRL) in condition-based maintenance decision-making for a system subjected to the competing and dependent risks of degradation and shock. Based on this system, the cost models of two quite simple policies implementing MRL-based or degradation-based preventive replacement are developed and compared with each other. Analyzing the equivalence and the performance of both policies allow us to give some conclusions on the interest of the MRL indicator.

Stochastic comparisons of imperfect maintenance models for a gamma deteriorating system

Abstract This paper compares two imperfect repair models for a degrading system, with deterioration level modeled by a non homogeneous gamma process. Both models consider instantaneous and periodic repairs. The first model assumes that a repair reduces the degradation of the system accumulated from the last maintenance action. The second model considers a virtual age model and assumes that a repair reduces the age accumulated by the system since the last maintenance action. Stochastic comparison results between the two resulting processes are obtained. Furthermore, a specific case is analyzed, where the two repair models provide identical expected deterioration levels at maintenance times. Finally, two optimal maintenance strategies are explored, considering the two models of repair.

Minimal Repair Models with Two Categories of Competing Failure Modes

This chapter reviews some maintenance models for systems subject to different failure modes called maintainable failure mode and non-maintainable failure mode. Each failure mode is associated with a failure rate and the failure modes compete to provoke the system failure. When the system fails, minimal repairs are performed. Preventive maintenance actions are carried out to mitigate the deterioration of the system due to maintainable failures. Non-maintainable failures are not disturbed by the successive preventive maintenance actions. Two different sections are analyzed in this chapter considering independent failure modes independent failure mode and dependent failure modes dependent failure mode.