A new model for reliability optimization of series-parallel systems with non-homogeneous components

In discussions related to reliability optimization using redundancy allocation, one of the structures that has attracted the attention of many researchers, is series-parallel structure. In models previously presented for reliability optimization of series-parallel systems, there is a restricting assumption based on which all components of a subsystem must be homogeneous. This constraint limits system designers in selecting components and prevents achieving higher levels of reliability. In this paper, a new model is proposed for reliability optimization of series-parallel systems, which makes possible the use of non-homogeneous components in each subsystem. As a result of this flexibility, the process of supplying system components will be easier. To solve the proposed model, since the redundancy allocation problem (RAP) belongs to the NP-hard class of optimization problems, a genetic algorithm (GA) is developed. The computational results of the designed GA are indicative of high performance of the proposed model in increasing system reliability and decreasing costs. •In this paper, a new model is proposed for reliability optimization of series-parallel systems.•In the previous models, there is a restricting assumption based on which all components of a subsystem must be homogeneous.•The presented model provides a possibility for the subsystems’ components to be non- homogeneous in the required conditions.•The computational results demonstrate the high performance of the proposed model in improving reliability and reducing costs.