Structured fault tree synthesis based on system decomposition

The purpose of this article is to explain how to decompose a system so that its fault trees can be synthesized more efficiently and in a structured and recursive manner. Under such a decomposition, modules such as control/trip loops will be regarded as dummy units at first so that the system size can be reduced significantly and dramatically. The fault tree of a top event can thus be constructed as follows: the one for the reduced system is synthesized first and then each of its terminal events, when these are events of a dummy unit, will be further developed. In order to carry out such a synthesis automatically, each dummy unit must be tried first, in order to be standardized, so that its unit-model can be established, and then saved in a database in advance. A suitable system input format must also be designed so that the fault tree can be synthesized automatically simply by keying-in the top event and the system.