Abstract: In view of the state space explosion problem in the process of system reachability diagram for state/event fault tree,a method of system failure reachability diagram based on temporal relation was proposed in this paper.By ana-lyzing the relationship between the triggering and the triggered event,the sequence of events are sorted.According to the temporal relation,all the pairs of the unreachable states of the system components can be obtained.Through establishing the Cartesian product of the reachable state of the components,all the reachable states of the system can be obtained.According to the connection table and the minimum cut set,the system can obtain the state reachable graph of the system failure,which effectively solves the problem of state space explosion in the generation process of the system failure map.The system failure reachability graph method based on sequence relation is used to generate the reachability graph of the torpedo attack system.The experiment verfied the feasibility and stability of the method.And the experiment shows that the method can alleviate the problem of state space explosion effectively,and provide a new method for the system to generate the system reachable graphs.

Key words: State/Event fault tree,Temporal relation,System failure reachability graph,State space explosion