Reliability Analysis And Optimization Of Key Parts Of Railway Turnout Cleaning Machine

Railway sieving machine is a kind of railway maintenance equipment that regularly replaces the ballast of the railway track bed.The large-scale railway sieving machine is expensive and is not suitable for the sieving of the ballast of certain single-open turnout sections of the railway with short distances and limited time requirements.Therefore,our research team preliminarily designed a small railway turnout ballast-cleaning machine,which can replace the existing tools to cooperate with workers to complete the most difficult ballast ballast-cleaning work under the sleeper.The reliability of key parts of the turnout ballast-cleaning machine will directly affect the working performance and life of the ballast machine.Therefore,based on the preliminary completion of structural design,the paper carried out reliability analysis and structural improvement design of the whole machine,and optimized design and reliability evaluation of key components.The main contents are as follows:(1)Introduce the working principle of the turnout ballast-cleaning machine,use the FMEA method to analyze the reliability of the turnout ballast-cleaning machine,list the possible causes of equipment failures and put forward improvement measures.The risk priority factor of the device is too large and needs to be improved.(2)Based on the reasonable calculation of the ballast-cleaning resistance,the structure improvement design and FTA analysis of the ballast-cleaning device of the railway turnout ballast-cleaning machine were carried out.The fault tree of the ballast-cleaning device is established,the minimum cut set of the fault tree is found,the normal fuzzy number is introduced in the quantitative analysis of the fault tree,and the method of combining normal fuzzy theory and expert comprehensive evaluation is used to take the top event and remove the bottom event.The importance of the bottom event is expressed by the distance between the top event and the top event after the bottom event is removed,and it is concluded that the key components of the ballast-cleaning device are the claw and the driving sprocket shaft.(3)On-site sampling the ballasts of a railway turnout section and constructing the corresponding irregular ballast particles in the EDEM.The Hertz-mindlin with bonding model is used to simulate the bonding state of ballast between particles,and discreteelement method is used to simulate the cleaning process of ballast.The load spectrum of the harrow claw in one working cycle is obtained;comparing the simulation results of the load of the harrow claw under different motion parameters to obtain the optimal parameters of the harrow claw during working;The load data of harrow claw are analyzed by K-S hypothesis test method,and the probability density distribution function of the load data of harrow claw is obtained.The stress-strength interference model of the harrow claw is established,and the structure reliability of the improved harrow claw is evaluated by using the Monte Carlo Method in ANSYS / PDS.The results show that the reliability of harrow claw strength is 100% under the condition of 95% confidence and 1000 sampling simulation data,and no fracture failure will occur.(4)The sprocket driving shaft has the characteristics of large length-to-diameter ratio,more supporting parts,and unbalanced force.To ensure its reliability,static analysis and modal analysis of the sprocket driving shaft are carried out,and the maximum equivalent stress,the maximum deformation and the natural frequency of the driving shaft are calculated by simulation;considering the influence of dimensional factors on the deformation and resonance,the response surface method based on genetic algorithm is used to optimize the size of the driving shaft.After the optimization of the driving shaft,the natural frequency is increased and the maximum deformation and quality are reduced;the reliability model of the driving shaft stiffness is further established,and the Six Sigma module in ANSYS Workbench is used to evaluate the reliability of the optimized driving shaft.The optimized driving shaft stiffness reliability is 97.75%,which has higher reliability.The research contents of the thesis laid the foundation for the laboratory development of the railway turnout ballast-cleaning equipment,and the research theory and method have certain reference value for the development of similar kind of equipment.