Reliability Analysis Of Shearer Hydraulic System Based On Discrete Time Bayesian Network

When the hydraulic system of shearer fails,there are not only static failure behavior between components,but also dynamic failure behavior.The traditional fault tree analysis method can only describe the static failure behavior,while the dynamic fault tree can solve the complex system modeling problem with static and dynamic failure behavior,but it can not be solved directly by quantitative analysis.Bayesian network has the advantage of analyzing and reasoning uncertainties.Combining Bayesian network with dynamic fault tree,the discrete-time Bayesian network analysis method and importance algorithm based on dynamic fault tree are studied.The problem of describing static and dynamic failure behavior between components in hydraulic system and solving dynamic fault tree is solved.Firstly,the static and dynamic failure behavior of hydraulic system is studied.The failure modes and failure mechanisms of common hydraulic components and systems are analyzed,and the dynamic fault tree model is established by using static and dynamic logic gates to describe the static and dynamic failure behaviors among components in the hydraulic system.Secondly,the discrete-time Bayesian network analysis method based on dynamic fault tree is studied.The construction of discrete-time Bayesian networks,conditional probability tables and the algorithm for solving leaf node failure probability and root node posterior probability are given.The feasibility of the method is verified by comparing the results of dynamic fault tree solved by Monte Carlo method with those obtained by Monte Carlo method.Then,in order to measure the impact of component failure on system failure probability,based on the existing fault tree and static Bayesian network importance algorithm,the probability importance,critical importance,F-V importance and comprehensive importance algorithm of root node of discrete-time Bayesian network are studied,and the results are compared with those of static Bayesian network analysis method to verify the rationality and feasibility of the algorithm.Finally,the reliability of the hydraulic system of electric haulage shearer is analyzed by using the discrete-time Bayesian network analysis method based on dynamic fault tree and the importance algorithm.The failure probability of the system in each time period and the posterior probability,probability importance,critical importance,F-V importance and comprehensive importance of the components in each time period are obtained,which provides a basis for finding the weak links of the hydraulic system and improving the reliability of the system.