A general preventive maintenance framework of a production system considering dynamic maintenance accessibility

In this paper, we investigate the maintenance problem of a production system where maintenance delay and dynamic environmental accessibility are considered. The system can be a single-component system or a series system with multiple components. It operates in a dynamic environment modeled by a discrete time Markov chain. The impact of the environment is twofold. Both the system productivity and the maintenance process depend on the environment state. Maintenance delay is taken into account in this work, such that the maintenance crew needs non-negligible times to arrive for maintenance activity. In addition, maintenance executing times are also non-negligible. We propose a preventive maintenance framework for a general production system. The component(s) are aging with time, described by their degradation levels or the time elapsed since their last renewal epochs, depending on their failure characteristics. For a specific maintenance scheduling, some reliability and production measure indexes such as the availability, environmental accessibility ratio and production loss rate are proposed to assess the system characteristics. The maintenance cost in the long-run horizon is also derived. We solve these problems in the framework of a semi-regenerative process. To further illustrate the properties of the policy, we show how the model is adaptive to single-component systems in detail. An example concerning a two-component production system is also presented. The model can provide theoretical references for decision-makers when maintenance delay and dynamic maintenance accessibility needs to be taken into account.