G-mixed: A new strategy for redundant components in reliability optimization problems

Abstract

Improving system reliability without increasing system cost or weight is a realm of great attraction for system designers. This objective can be achieved by developing new redundancy strategies that improve system reliability by changing the activation time of redundant components. In this paper, a new unified redundancy strategy called “G-mixed” is introduced. The G-mixed strategy is a general form of previous redundancy strategies, which can be converted to all other forms. In this strategy, the number of components that have to be kept in active mode is considered as a decision variable and optimized by a mathematical model. The efficiency of the proposed strategy is investigated in different problem instances. Results indicate that, in most cases, the new G-mixed strategy outperforms the previously reported ones including the K-mixed, mixed, standby, and active counterparts. Another aspect of the study involves determining the superiority of different strategies under different combinations of component and switch reliabilities. It is found that switch unreliability has the least effect on the efficiency of the proposed strategy when compared with those that require a switching system.