Hierarchical Interaction and Fault Abstraction Framework for Complex Engineered Systems

Complex engineered systems (CES) consist of interconnected components with intricate interactions, making early-life failure diagnosis, particularly those stemming from manufacturing processes, highly challenging. Minor deviations in process parameters can affect components and subsystems, potentially leading to system-wide failures. Manufacturing deviations in individual components, though not necessarily fagged as defects, can combine in unexpected ways, causing broader system failures. Diverse fault pathways often produce similar failure symptoms, further complicating root-cause analysis. This paper introduces the Hierarchical Interaction and Fault Abstraction Framework (HIFAF) to represent the relationships among components, manufacturing processes, associated failure modes, and causal fault events for complex engineered systems. By integrating failure modes and fault events as intermediate nodes, the framework captures fault interactions with a level of abstraction, offering a structured approach to managing complexity. Realized as a knowledge graph, it provides a clear visualization of fault interaction pathways, supporting diagnostic processes. The framework is demonstrated through a case study on a single-stage gearbox system manufactured in-house, showcasing its ability to represent system-level failures and their links to minor manufacturing process deviations, revealing unexpected fault interactions.