A FAILURE-REPAIR MODEL WITH MINIMAL AND MAJOR MAINTENANCE

A Markov model is proposed for a continuously operating device whose condition deteriorates with time in service. The model incorporates deterioration & Poisson failures, minimal repair, periodic minimal maintenance, and major maintenance after a given number of minimal maintenances. An exact recursive algorithm computes the steady-state probabilities of the device. A cost function is dermed using different cost rates for the different types of outages. Based on minimal unavailability or minimal costs, optimal solutions of the model are derived. Major maintenance is found seldom beneficial if optimal maintenance intervals are used. If a maintenance policy is based on non-optimal intervals between maintenances, periodic major maintenance can reduce costs in some cases.