A New Dynamic Fault Tree Analysis Method And Application In Hydraulic System

The dynamic failure characteristics of the components of hydraulic system, such as dynamic, sequence, redundancy and correlation can not be described by static fault tree, and there always exists the problem of data explosion during the failure probability of the top event is solved by the existing dynamic fault tree. In order to solve the problems above, a new dynamic fault tree analysis method is proposed based on the research of traditional static fault tree, T-S fault tree and the existing dynamic fault tree method. Then, a new algorithm for the importance of the new dynamic fault tree analysis method is proposed. Finally, the reliability of the hydraulic system of the numerical control machine tool is analyzed by the new dynamic fault tree analysis method and the new importance algorithm.Firstly, a new dynamic fault tree analysis method is proposed based on the static fault tree and the existing dynamic fault tree. Not only can the method obtain the failure probability within the mission time, but also obtain the failure probability of each time period in the mission time. During the solving process, it provides basis for reliability analysis of the system in any time period. Compared with the traditional static fault tree, T-S fault tree and the existing dynamic fault tree analysis method, the feasibility and broader applicability of the proposed method is verified.Secondly, as an important quantitative of fault tree analysis method, importance algorithm reflects the importance of the basic events or cut sets of the system. The probability importance and critical importance algorithm of the new dynamic fault tree analysis method are put forward based on the new dynamic fault tree analysis method. The new algorithm, based on the physical meaning of the probability importance and the criticality importance, describes the importance of bottom events with dynamic failure characteristics. Compared with the traditional static fault tree, T-S fault tree probability importance and criticality degree algorithm, the feasibility of the method is verified.Finally, the computer numerical control machine tools are the important manufacturers of other equipment in equipment manufacturing industry and their reliability level has now become the bottleneck which restricts the industry development. The new dynamic fault tree analysis method and importance algorithm are applied to the reliability analysis of the hydraulic system of the numerical control machine tool. The failure probability of the top event, the probability importance and the critical importance of each basic event are solved, which provide basis for enhancing the reliability, fault diagnosis and condition maintenance based on reliability of the hydraulic system of the computer numerical control machine tools.