Reliability redundancy allocation optimization for multi-type production system

System reliability optimization is a central topic in reliability engineering, and enhancing system performance remains a significant research focus. This study investigates a multi-type production system composed of parallel production lines, where each line can fulfill a range of manufacturing requirements through serially connected subsystems. The research examines reliability optimization by allocating redundancy in the subsystems of the production lines, considering both active and cold standby redundancy strategies. Based on importance measure theory, two component adjustment strategies are proposed to enhance the subsystem reliability. An efficient multi-objective algorithm, known as Birnbaum importance-based NSGA-Ⅱ (BI-NSGA-Ⅱ), is constructed following the fundamental procedure of the NSGA-Ⅱ. The effectiveness of the proposed algorithm is validated through simulations involving two numerical case studies. The results provide valuable insights for guiding the reliability design of multi-type production systems.