Research On Maintenance Strategy Of Mine Loader Based On Time-varying Reliability

With the rapid development of chinese economy,the demand for mineral resources is increasing,the scale of mining is rapidly expanding,and a large number of mine loader are put into production activities.Mining companies have a relatively weak awareness of the maintenance of loaders,and they are still stuck in a maintenance mode that combines post-repair and regular maintenance,resulting in frequent shutdowns and increasing maintenance costs for the company.Therefore,it is urgent to study the reliability and maintenance strategy of mine loaders,which is of great significance to enterprise operation management and production efficiency.In order to reduce maintenance costs and improve availability,this thesis studies the maintenance strategy of mine loaders based on reliability theory.The specific contents are as follows:First,analyze the functional structure of the mine loader to divide the subsystems,combine the collected mine loader maintenance records,and use the FMEA method to determine the key subsystems of the whole machine as the power system,transmission system and hydraulic system.The median rank method and the least square method are used to fit the reliability distribution of each key subsystem,and the K-S test method is used to test the reliability function and failure rate function.Secondly,in order to describe the repair effect of maintenance activities and the degradation of equipment performance,the service age regression factor and the failure rate increasing factor are introduced to construct a mixed failure rate model,and the mixed failure rate model is combined to establish a time-varying reliability model.Based on the time-varying reliability,a single-system preventive maintenance strategy model with the goal of minimizing maintenance cost rate is constructed,and the power system,transmission system and hydraulic system are solved separately to obtain the maintenance strategy of each key subsystem.Finally,in order to ensure availability and reduce maintenance costs of the whole machine,based on the single-system preventive maintenance model,the structural relevance of each key subsystem of the loader and the economic relevance of maintenance activities are considered,and the total maintenance cost is minimized.The model of opportunistic preventive maintenance based on time-varying reliability with the goal of maximizing availability.The linear weighting method is used to combine the two opportunistic maintenance models to establish a dual-objective opportunistic maintenance strategy model.The genetic algorithm is used to solve the dual-objective opportunistic maintenance model of mine loader,and the best opportunistic maintenance strategy is obtained.The comparison and analysis with the single-system preventive maintenance strategy verify the effectiveness of the model.The research results of this paper have guiding significance for the maintenance strategy formulation of mine loader,and also have certain reference value for the maintenance strategy of other construction machinery.