Availability and maintenance modelling for systems subject to multiple failure modes

The availability and optimal maintenance policies of a competing-risk system undergoing periodic inspections are studied in this paper. Specifically, a repairable system with a working state and M failure modes is considered. Each failure mode has a random failure time. When the system fails from the ith (i = 1, 2,..., M) failure mode, corresponding corrective repair is performed which takes a random time Y-i (i =1, 2,...,M). Some analytical results on the instantaneous availability and the steady-state availability for the system are derived. The model is then utilized to obtain the optimal inspection interval that maximizes the system steady-state availability or minimizes the average long-run cost rate. A numerical example for Remote Power Feeding System is presented to demonstrate the application of the developed approach. (C) 2017 Elsevier Ltd. All rights reserved.