Maintenance Cycle Decision Of Key Metal Parts Of High-Speed EMU Based On Importance

The maintenance of high speed EMUs is the key to ensure safe and reliable operation,and the maintenance work is carried out based on the cycle.However,the maintenance cycle of high speed EMUs in China indiscriminately copies foreign countries’ class and system,which only emphasize high reliability of metal parts,resulting in "excessive maintenance","insufficient maintenance",resource waste and high cost.Therefore,it is of great significance to research the maintenance cycle decision of the high speed EMU key metal parts.The maintenance cycle decisions in this paper are proposed according to the maintenance intervals.Firstly,the main factors affecting the importance of the high speed EMU metal parts are analyzed from three aspects which are reliability,economy and maintainability.Based on improved fuzzy analytic hierarchy process,the importance of metal parts is evaluated and the levels of the parts are classified according to the results of the evaluation.Secondly,in view of failure or zero failure operation and maintenance data of metal parts,different life models are discussed respectively.Aiming at failure data,residual ratio method is applied to estimate the parameters of life model.As for the zero failure data,the parameter estimation of Weibull distribution is used by combining the distribution curve method and the E-Bayes method.And based on the life model and part level,the maintenance cycle decision model for improvement factors is established under the requirements of economy and reliability,and following the process of deterioration of parts,a decision model for phase and sequence is built.Then,a maintenance decision system for metal parts of high speed EMU is developed by applying the basic development tool VB and hybrid programming of Matlab and Access.Finally,taking the brake pad of CRH5A EMU as an example,the new maintenance cycle is put forward.Compared with the former one,the suggested cycle is prolonged 40,000 kilometers,and although the reliability is reduced,it is between 0.6 and 0.7 still within the acceptable range.The references for the maintenance cycle decision of other metal parts of high speed EMUs are provided through the analysis of the brake pad.