SySTEMA SYstem & Safety Tool for Executing Model-Based Analyses

This paper presents SySTEMA, an innovative approach to perform Safety Analyses on complex systems, based on the modelling of their functionalities, behaviors and architecture. System safety analysis techniques are well known and are extensively used during the design of safety-critical systems. Since these analyses are highly subjective and dependent on the skill of the practitioner, it is unlikely that they will be complete, consistent and error free. In fact, the safety engineers devote much of their effort to find undocumented details of the system behavior and to embed this information in the safety artifacts such as the fault trees. Most of the review effort is focused on uncovering and resolving misunderstandings and missing information in the system design or the informal fault model. Model-Based Systems Engineering (MBSE) is a methodology aiming to design and develop complex and/or critical systems, increasing productivity by promoting communication among different teams working on the same project. Model-Based Safety Analysis (MBSA) is an emerging discipline that extends MBSE performing safety analyses in a ‘model-based’ context, by building system models (both for nominal and fault behavior), reducing the effort and increasing the quality of the final results. MBSA follows a failure analysis approach, starting from the major state-of-the-art techniques such as Failure Mode Effect and Criticality Analysis, Functional Analysis, Functional Hazard Analysis and Fault Tree Analysis. This paper describes a theoretical approach to implement MBSA using one common SysML model of the system. This allows the systems engineers to perform automated safety analyses to receive quick feedback on their design decisions during the system design phase. Keywords—MBSE; MBSA; SysML; FMEA; FTA.