Joint optimization for inspection and replacement model based on a three-stage failure process

Preventive maintenance (PM) is still a dominant policy in industry and inspections are necessary PM activities. An inspection model based on a three-stage failure process under the age-based preventive replacement policy for a single component system is proposed. The three-stage failure process divides the lifetime of the system into four states: normal, minor defective, severe defective and failure, which is closer to reality. The system is renewed at the time that the severe defective stage is identified and at failure. Moreover, the system is replaced once reaching the certain age T under the age-based replacement policy. However, two different cost models are proposed depending on the different options at the time of identifying the minor defective stage. A numerical example is presented to demonstrate the efficiency of the proposed models. © 2015, The Society for Reliability Engineering, Quality and Operations Management (SREQOM), India and The Division of Operation and Maintenance, Lulea University of Technology, Sweden.