A Functional Failure Analysis Method of Identifying and Mitigating Spurious System Emissions From a System of Interest in a System of Systems

Increasingly tight coupling and heavy connectedness in system of systems (SoS) present new problems for systems’ designers and engineers. While the failure of one system within a loosely coupled SoS may produce little collateral damage beyond a loss in SoS capability, a highly interconnected SoS can experience significant damage when one member system fails in an unanticipated way. It is therefore important to develop systems that are “good neighbors” with the other systems in an SoS by failing in ways that do not further degrade an SoS’s ability to complete its mission. This paper presents a method to (1) analyze a system of interest (SoI) for potentially harmful spurious system emissions (failure flows that exit the SoI’s system boundary and may cause failure initiating events in other systems within the SoS) and (2) choose mitigation strategies that provide the best return on investment for the SoS. The method is intended for use during the system architecture phase of the system design process when functional architectures are being developed, and analysis of alternatives and trade-off studies are being conducted2.