Reliability of phased-mission systems subject to competing failures

This paper considers the reliability analysis of phased-mission systems (PMS) subject to competing failure propagation and failure isolation effects. A propagated failure with global effect (PFGE) originating from a system component is a failure that causes damage to all other system components besides the component itself. However, in systems subject to the functional dependence (FDEP) behavior, the failure of a trigger component can make the system insensitive to PFGE originating from the dependent components, i.e., the failure isolation effect. On the other hand, if the trigger component is still functioning when the PFGE of a dependent component happens, the failure propagation effect takes place causing the entire system failure. In summary, there exists competition between the failure isolation and failure propagation effects. Existing works addressing the above described competing failures focus only on single-phase systems. In this work, we propose a combinatorial algorithm for the reliability analysis of non-repairable PMS subject to the competing failures. The proposed approach is applicable to different types of time-to-failure distributions for the system components. A case study is given to demonstrate application and advantages of the proposed method.