1Systems Failure and Safety Assessment Using Integrated Petri Net Modeling and Fault Tree Analysis Approaches

Current methods in combining Petri net modeling with fault tree analysis for systems failure and safety assessment assume that the failure rates of the basic events in a system are the same and the Petri net model of the system consists of only simple structures. These assumptions do not reflect the real industrial applications for system failure and safety analysis. To overcome the limitations of the current methods for systems failure and safety assessment, this paper extends the current methods to real applications where basic events can have different failure rates and the systems can be modeled with complex Petri net structures. Examples of failure and safety analysis of a nuclear waste carrying manipulator and an automated manufacturing and assembly system with a robot are provided to demonstrate the developed method. Key words: Petri nets, fault tree analysis, system reliability and safety, failure rates. * To whom correspondence should be addresse