Analysis of fault tree base on uncertainty measure

Based on uncertainty measure theory, this paper proposes a method that constructs and analyzes fault tree. In fault tree this paper, it would be characterized as crisp number if fault rate of bottom event is obtained from reliable handbook, empirical data and so on; it would be characterized as uncertain variable if fault rate of bottom event has no statistical data but is obtained from expert´s subjective judgment. The expected value of overall system´s top event is calculated by using uncertain simulation technology. Finally feasibility and validity of this method is confirmed by taking fault tree of internal combustion engine as example.