A new methodology for preventive maintenance of degrading items is discussed. It combines the classical age-replacement strategy when a system is replaced either on failure or on reaching the predetermined age, with replacement on reaching the predetermined level of deterioration at some intermediate time. Degradation of an item is modeled by the nonhomogeneous gamma process, whereas its failure occurs when this process reaches the predetermined deterministic level. It is shown that the proposed policy outperforms the classical one, i.e., it achieves the lower value of the corresponding long-run cost rate. The detailed numerical illustration is presented, and the relevant sensitivity analysis for the main parameters of the model is performed.
Bibliographical noteFunding Information:
The authors greatly thank the reviewers for helpful comments and advices. The work of the second author was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (Grant 2019R1A2B5B02069500). The work of the second author was also supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant 2019R1A6A1A11051177).
© 2020 John Wiley & Sons, Ltd.
- age replacement
- gamma process
- gradual failure
- long-run cost rate
- preventive maintenance