Integration of a model-based systems engineering framework with safety assessment for early design phases: A case study for hydrogen-based aircraft fuel system architecting

Novel hydrogen-based aircraft concepts pose significant challenges for the system development process. This paper proposes a generic, adaptable, and multidisciplinary framework for integrated model-based systems engineering (MBSE) and model-based safety assessment (MBSA) for the conceptual design of complex systems. The framework employs a multi-granularity, model-centric approach, whereby the architectural specification is utilized for design as well as query purposes as part of a qualitative and quantitative, graph-based preliminary safety assessment. For the qualitative assessment, design and safety rules based on existing standards and best practices are formalized in the model and applied to a graph-based architecture representation. Consequently, the remaining architectures are quantitatively assessed using automated fault trees. This safety-integrated approach is applied to the conceptual design of a liquid hydrogen fuel system architecture as a novel, uncertain, and complex system with many unknown system interrelations. This paper illustrates the potential of a combined MBSE-MBSA framework to streamline complex, early-stage system design and demonstrates that all qualitatively down-selected hydrogen system architecture variants also satisfy quantitative assessment. Furthermore, it is shown that the design space of novel systems is also constrained by safety and certification requirements, significantly reducing the number of actual feasible solutions. • Development of a multidisciplinary and integrated MBSE and safety assessment framework for conceptual systems architecting. • Enhance the architecture modeling approach to serve as the single source of truth for specification and safety assessments. • Adaption to the graph-based architecture representation to allow for LH2 as a fuel type. • Identification and collection of H2 design and safety rules formalized in the architecture model. • Automation of preliminary safety assessment with the integrated MBSE-MBSA framework.