Redundancy optimization for series-parallel phased mission systems exposed to random shocks

Systems performing consecutive non-overlapping mission phases in a random environment are considered. Each phase is performed by a specific 1-out-of-n subsystem consisting of statistically identical parallel elements with the same functionality. The environment is modeled by the Poisson process of shocks commonly affecting all elements, by increasing their failure rate. A method for evaluating the mission success probability for arbitrary redundancy level in each subsystem is presented. The constrained redundancy allocation problem is formulated and solved. Illustrative examples are presented. (C) 2017 Elsevier Ltd. All rights reserved.