Dependability modelling and evaluation by using stochastic Petri nets: application to two test cases

The systems modelling and the assessment of their performances are the two key phases of any reliability or risk analysis study. However, it is well known and admitted that most of the methods devoted to this goal are unsuitable if the physical behaviour of the systems cannot be made independent from the probabilistic behaviour, as is the case for dynamic process systems. To overcome this inefficiency, some alternative methods have recently appeared. But they are not very approachable and could be, for this reason, ignored by most of the practitioners. Among these methods, however, simulation methods should be confirmed. From this point of view, the authors propose a straightforward approach to this problem by using stochastic Petri nets on a simple and well-known dynamic system from the literature. In addition, for testing this approach, the authors have carried it out on a system with periodically tested components. The results obtained are compared to those already published, the limits of the method are underlined and its efficiency in solving this kind of problem is being examined.