| Mechanical system is an oganic system in which function can be classified into diferent levels. All fault events of all the systematic components make up a discrete event dynamic system. Among these fault events exist complicated logical relations, such as successivity and concurrence. Sufficient consideration of fault germination, development and spreading is required in the domain of remained life prediction of mechanical system. In the tranditional predicting methods, the remained life of certain pivotal parts on particular breakdown patten was regarded as the remained life of the whole machine. Mathematical statistics was also used to obtain the mean remained life of machinery because of incomprehension on the mechanism of fault development. Although these methods can meet the end in some extent, they are restrictly applied owing to the inconsideration of the constitution in machine or deficiency of universal fitness. In order to predicate the remained life of particular machine under special working conditions, a mathematical model will be developed that can be used to describe the logical relations among fault events and emulate the dynamic development process of complicated faults. On the base of thorough analysis of fault characters, the Petri net model is introduced and changed into Fault Petri net (FPN) that can be used to settle some critical problems such as complicated faults, degradation competition and one cause with multiple consequence according to the characters of fault evolvement and spreading. In order to predicate the remained life of particular machine under special working conditions, an algorithm was also providcd to analyse the timely characters of the FPN. It is demonstrated that the method provided in this paper can simulate the dynamic evolvement process more appropriate than tranditional methods such as Fault Tree Analysis (FTA) and can predicate the remained life of the particular machine under special working conditions.
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