Extending the Shell Model via Cause/Consequence Analysis of Component Failures

The Shell Model Analysis is a method for use at a very early lifecycle stage, delineating and providing insight into newly to-be-developed systems. Its findings and results can be used as inputs for further analysis methods, as discussed in this paper. With focus on function-message chains (FMCs) spanning through the system, a Shell Model Analysis can be linked to established methods, e.g. an FMEA, or an FTA. This paper investigates an adapted form of these two methods in combination with the Shell Model Analysis, for identifying causes and consequences of behavioural deviations in a structured and guided way. The identified deviations can be apportioned to the different components within the system, thus defining specific top-level requirements upon them. These requirements should be forwarded to the component suppliers, to enhance system quality and safety.