Imperfect Maintenance Policy Considering Positive and Negative Effects for Deteriorating Systems With Variation of Operating Conditions

This brief develops a degradation-based imperfect maintenance policy considering both positive effect and negative effect for a deteriorating system with variations of operating conditions. The proposed method improves the positive effect on the imperfect maintenance, which further considers the impact of resource on the distribution function of the positive effect after each maintenance process. The positive effect induces the system state into a random interval which is related to maintenance resource applied into each preventive maintenance action and actual maintenance times. Meanwhile, a new negative deteriorating effect model for describing the impacts of imperfect maintenance actions is established. The new model considers that the degradation rate increases after each imperfect maintenance process; meanwhile, it includes the impacts of variations of operating condition bringing to the degradation rate which is described as a distribution subjected to stress as well. Therefore, a condition-based adaptive maintenance policy is applied for a deteriorating system. The optimal maintenance cost allocation and maintenance threshold are determined by maximizing an availability function. Finally, a numerical example is illustrated to demonstrate the application of our maintenance model and policy.Note to Practitioners—This paper was motivated by the problem of computing an optimal commonly agreeable maintenance policy for a deteriorating system to make it running at the longest life span at the limited maintenance cost budget. Consider maintenance effect with maintenance resource, maintenance times, and some other uncontrollable factors to establish a reasonable maintenance schedule for a deteriorating system. The existing approach is to describe the imperfect effect with just assuming that the deterioration level after each preventive maintenance action can be decreased into a fixed variable interval without any distinguished difference. It is thus highly desirable for a deteriorating system with such various operation conditions to have a mechanism that would take into account each maintenance resource arrangement and various stress levels. To come up with a reasonable maintenance model, in this brief, we just assume that maintenance effects are divided into two terms: a positive effect model which induces the system state into a random interval which is related to per maintenance cost which is described as a power function and actual maintenance times. Meanwhile, a negative deteriorating effect model is established for describing the impacts of imperfect maintenance actions on the degradation rate with an increasing trend just like the accelerating process after each maintenance action. This maintenance model can solve the problem involved maintenance source arrangement. The users can develop an optimal maintenance schedule in advance. It would be updated in real time based on the change in environmental stress level.