System reliability assessment incorporating interface and function failure

This paper proposes a new perspective and method to model system reliability by analyzing a system's functional and interface/interaction failure. System failure is evaluated based on the functions that a system is designed to deliver. Functional failures can be attributed to physical component-level failure as well as the interface failure. A new system reliability modeling framework is developed to quantify the reliability performance through system function and interface analysis. Interfaces failure and possible multiple functions failure can then be integrated into the traditional fault tree and reliability block diagram reliability analysis. The research is motivated by the high proportion of Non-Defect Found or “NDF” in failure analysis of complex engineering systems, which has been attributed to the lack of interface failure analyses. The proposed function and interface analysis based system reliability method is demonstrated through assessing and modeling the reliability of a power assembly system in a diesel-electric engine.