Reliability Evaluation And Allocation Of A Large Mining Excavator Based On Failure And Maintenance Data

As important engineering machinery in the mining and construction project, large mining excavators represent the mining capacity and technology levels of a country, and reflect the overall levels of equipment manufacturing industry, with its wide application and high value. With the rapid development of world economy, the mining scale of open-pit mines is rapidly expanding, but a large number of mining accidents and excavator failure problems are emerged at the same time. Therefore, the reliability study on large mining excavator can enhance the international competitiveness of China’s mining machinery, and it is significant on utilization of the national mineral resources with high efficiency and safety.In this paper, from the project of large mining excavator reliability analysis, the reliability evaluation and reliability allocation of large mining excavator are researched with the following several aspects.Firstly, the large mine excavator are divided into several subsystems, according to the requirements of reliability analysis and relative literatures. Then the structure and function of each subsystem and component are clarified to lay the foundation for reliability analysis and following works.Secondly, with the failure and maintenance data, the failure mode and effects analysis(FMEA) on large mining excavators can be finished. All possible failure modes and mechanism can be pointed out,then all causes and adverse consequences of these failure problems can be analysed, so as to find out the weak link in the design and manufacture process of large mining excavator, as well as the key subsystems and components.Thirdly, considering the lack of excavator reliability data, the reliability evaluation job can mainly base on the failure and maintenance data. After the processing of failure and maintenance data, and statistical time data between failures, the parameters of the distribution function can be estimated, using the kernel density estimation method for calculating cumulative distribution function. According to the reliability distribution function, the reliability indexes calculation and evaluation of large mining excavator can be calculated. The proposed evaluation method, directly based on objective fault data, avoids the subjective factors and has the stronger engineering application value compared with the traditional methods.Finally, the reliability allocation indexes can be allocated on the key subsystems and components of excavator, which are determined by the large mining excavator failure mode and effect analysis. The failure frequency and average maintenance time resolution(MTTR) of each key subsystem and component can be caculated based on the analysis of failure and maintenance data, as reliability factors of computing distribution factor. Then the MTBF can be uesed as the reliability allocation index, for the reliability allocation of each key subsystem, using the entropy method. The proposed method, compared with the traditional methods, has a better visuality and simplicity, as well as suitability for the practical engineering application.