Keywords: safety patterns, reuse, safety analysis, automated FTA, automated FMEA, failure modelling, fault simulation, failure mode and effects analysis, generalised failure logic, reusable failure behaviour, failure patterns, component failure, brake-, by-, wire, fault tree analysis, safety critical systems
Capture and reuse of composable failure patterns
Emerging safety analysis techniques use composition of failure models or fault simulation in formal models of a system to determine relationships between the causes and effects of failure. Most recent work has focused on developing system modelling and algorithms for automatic safety analysis. However, little work has focused on developing principles to improve reuse of safety analyses in the context of these techniques. In this paper, we describe a generalised failure logic (GFL) that can capture abstract reusable characteristics of failure behaviour and show how the GFL can be used with templates for the specification of reusable and inheritable component failure patterns. Finally, we illustrate how such patterns can be used with HiP-HOPS, an automated fault tree and FMEA synthesis tool, in order to simplify safety analysis while formalising and improving reuse. Benefits of this approach are discussed in the light of a case study on a brake-by-wire example.