A stochastic hybrid automaton case study

Among the quantitative RAMS methodologies, Fault Tree Analysis (FTA) and Reliability Block Diagrams (RBD) are the most famous since being adopted in the industrial sector from the early ’60s. These models are solved on the base of simple hypotheses to ease the quantitative computation: system’s components are defined by dyadic states; they are independent from each other and the working conditions in which the system operates are assumed steady. These three assumptions allow to model the failure/repair rate of the system components with a static probability density function, and to compute the probability of an undesired scenario using the simple relationships of the Boolean algebra theory. In order to capture the multi-state nature of industrial system’s components, at the state of the art, Stochastic Hybrid Automaton models (SHA) are emerging; they can consider the physical and the stochastic issues. The paper applies the above-mentioned methodology solving-by means of a pilot software application named SHYFTOO-a single item case study; the influence of aging and operative conditions on the system’s operations and performances are taken into account.