Multi-objective reliability redundancy allocation problem considering two types of common cause failures

Common cause failures actuate simultaneous failure in the components of system and can incredibly reduce the reliability of the system. So the evaluation of common cause failure rates and its effect on system reliability is very much significant. When common cause failures are considered, failure rate of the components are not independent. The influence of common cause failure (CCF) to system reliability has motivated to consider common cause failures in reliability redundancy allocation problem. So, a novel multi-objective reliability redundancy allocation problem is formulated here with the objectives of maximizing system reliability and minimizing system cost in the presence of common cause failures. In this article, two types of common causes are highlighted, namely fatal and non-fatal CCFs, in addition to random failures. These types of failures lead to simultaneous failure of multiple components because of a common cause. An attempt has been made for the first time to solve the multi-objective optimization problem using two meta-heuristic algorithms which gives the Pareto optimal solution. Since the rapid advancements in Science and Technology encouraged the researchers for the optimal design of complex systems considering different environmental situations, two numerical evidences based on complex systems has been considered here. The results indicate the reduction of optimal redundancy with two types of CCF when compared to random failure alone.