Fault severity analysis of the time-dependent mechanical systems by the revised Time Petri net

Abstract

This article presents a fault severity analysis model to assess the fault severity at different time intervals by the revised Time Petri net, which reveals the principle of the time-dependent failure and explores the weak links in the mechanical system. A revised Time Petri net is introduced in this article by extending the tuples of the ordinary Time Petri net. The basic functional units are defined by the revised Time Petri net logic symbols, and the time firing schedule as well as the state diagram which reflects the characteristics of the mechanical system is used to assist in modeling the fault propagation of the mechanical system in the early phase of design. A numerical example of the spacecraft solar array illustrates the revised Time Petri net–based modeling method, investigates the fault mechanism and realizes the weak links of the system. The proposed method is demonstrated by analyzing the failure history data of 100 spacecraft solar arrays to get proportion of the failures at the most dangerous time intervals. The results also reveal some special phenomena related to the time-dependent failure in the mechanical system of the solar array.