Research On Improving And Realizing Arithmatic Of Fault Tree Analysis

FTA (Fault Tree Analysis) beginning from 1960's is an important method to evaluate the reliability and usability of system. The early arithmetic limites the number of events, while the new one has not. It can analyze bigger coherent fault tree. Coherent fault tree as it is, it is right to have some non-events when these events can be removed through the non-operation. There is only two logic relations (and/or) between the events and the other logic relations can be converted to the two logic relations.Although the theory for the evaluation of the fault tree associated monotonically has been developed perfectly, it is also an emphasis in the paper how to use the theory available to optimize the program reasonably. According to the nondeterministic polynomial (NP) in the fault tree analysis, the amount of computation increases exponentially with the number of the basic events of a fault tree. To solve this problem, two measures, e.g. early-stage unintersection, modularization and transfer event are used with more repeated events and transfer event with no repeated events. Thus the analysis of the fault tree can descend exponentially.In the qualitative analysis, we take the method of Fussell and setting prime for every basic event with the different methods for storing the cut sets: queue-pointer and two-dimension array. It is clear that the queue-pointer is the better. For the cement clinker in the basic events and the elements of the minimal cut set, it needs to take late-stage unintersection to get the unintersection-implicant Sets of both the fault mode and normal mode. The result is suit for both the coherent fault tree and the non-coherent fault tree.