Optimal component sequence in heterogeneous 1-out-of-N mixed RRAPs

The present study revisits the reliability-redundancy allocation problem (RRAP), as the most important problem in the design phase of complex systems. It is investigated with heterogeneous components allowed, which makes it formidable to find the optimal component sequence in each subsystem. Furthermore, a mixed redundancy strategy is applied to subsystems whose reliability requires complicated and time-consuming calculations to determine. A Markov-based model is developed to address both these issues at a low computation cost. Finally, the proposed approach is implemented on two famous benchmark test problems. Results demonstrate that, compared to the previously reported solutions, the proposed approach yields much better structures with higher reliability values without increasing the cost or volume of the systems.