A condition-based maintenance strategy for heterogeneous populations

• Heterogeneous population.
• Cost criterion.
• Reliability criterion.
• Comparative analysis.

This paper develops a maintenance strategy, called inspection–replacement policy, to cope with heterogeneous populations. Burn-in is the procedure by which most of the defective products in a heterogeneous population can be identified and removed prior to being placed in service. However, modern manufacturing is so well developed that a defective product is able to function for a long period of time even under aggravated operational conditions. Instead of weeding defective products out via costly burn-in tests, use can be made of them in field operation where maintaining actions will be performed to prevent early in-use failures. The inspection–replacement policy consists of an inspection, conducted in an early stage with the purpose of identifying and replacing defective products, and a preventive replacement, carried out at a later stage to prevent wear-out failures. The preventive-replacement time is dynamically determined, depending on the information obtained by the inspection. The inspection–replacement policy is compared with a joint burn-in and age-based-replacement policy to show its practicability and competence.