Fault Tree-monte Carlo Method Simulation And Analysis&Sampling Scheme Research Of Reliability Test For Electric Multiple Unit (EMU)

As an indispensable step of Electric Multiple Unit (EMU) reliability research, EMUreliability test is the foundation of EMU design and reference of EMU maintenance. Faultanalysis is the important component of reliability assessment, while sampling inspection is thenecessary section of reliability test, thus developing reasonable sampling scheme is thecritical assumption to successfully implement reliability test. Currently it is still difficult tosee the application of Fault Tree-Monte Carlo Method on EMU reliability assessment andreliability test sampling plan appropriate to the characteristics of EMU. Therefore, aroundthese two directions about EMU Fault analysis and developing sampling inspection schemefor EMU, this paper carried out the following research work:(1)The fault tree models of the EMU system and its first subsystems were established,Monte Carlo method and MATLAB software were applied to simulate and analyze thereliability of the EMU. The results indicate that, the capability of Monte Carlo simulationmethods based on Fault Tree Analyzing to calculate the reliability of the whole EMU and testthe distribution type of malfunction rule of the EMU fast and accurately has beendemonstrated; Fault Tree-Monte Carlo Simulation proves that if the fault probabilities of theEMU’s basic components obey index distribution, so does the fault probability of the wholeEMU; the weak links of the EMU were analyzed, and the importance rank of the majorcomponents of EMU was provided.(2) Based on the hypothesis-testing theory the fault data of the EMU was analyzed,which demonstrated that the malfunction rule of the EMU obeys index distribution; in thepremise of this conclusion, based on the reliability sampling test theory, two sampling plansof reliability test sampling inspection for the EMU were made: one chooses several EMUsamples, with high accuracy and short test time; another one only chooses one EMU sample,with low accuracy, long test time. Taken together, if the EMUs are plentiful, in order to savetime and improve the accuracy, the first scheme should be adopted; if the EMUs areinadequate, but the test time is adequate, the second scheme should be adopted. These twoschemes both conform to reliability sampling test theory, should be chose reasonablyaccording to the number of EMU samples, test time, accuracy requirement in practicaloperation.