15. Combination of System Analysis Methods

One may ask how single analytical system analysis methods can be leveraged for technical-driven systems’ resilience engineering using key concepts of risk control. More comprehensively one can ask for suitable method combinations. The chapter presents exemplary discussions on method combinations for system reliability, safety, and resilience analysis and improvement. Selection and ordering principles include level of detail and completeness of methods, development processes, and the functional safety life-cycle assessment and development process of IEC 61508. To this end, appropriate earlier findings of the textbook are extended. One specific efficient combination is considered in detail: systems modeling language (SysML), hazard analysis (HA), failure modes and effects analysis (FMEA), fault tree analysis (FTA), and reliability prediction. It uses the example of an electric vehicle and the identification of faults in after sales scenarios. First, the chapter discusses the advantages of semi-formal modeling with SysML in combination with FMEA and FTA. Then the connection of HA to other system analysis methods and the combination of FMEA and FTA. It treats the aggregation of subsystem FTAs to a system FTA. Finally, it shows how FTA results can be used after product development to optimize error detection and repair by providing efficient failure isolation procedures, also called fault isolation procedures (FIP). This is an example for the engineering of resilience in the sense of fast stabilization, response, and recovery post potential disruptive events during operation of modern green transport systems.