Simulation Analysis And Research On Ballast Cleaning Machine Excavation Device And Track Bed

The track structure of China’s railways is mainly ballasted track.and it will deteriorate with its operating time increasing.It needs regular maintenance of large road maintenance machinery to ensure the normal progress of railway transportation.The ballast cleaning machine can solve part of the problems by cleaning and changing the ballast.While there is still little corresponding theoretical support for the research on the working state and stress of the excavation device of the ballast cleaning machine during the ballast cleaning process.This paper realizes the simulation of the excavation chain operation process,analyzes the simulation results and provides a theoretical basis for the optimization of the ballast cleaning machine.Create a discrete element model based on the real ballast bed.The ballast gradation relationship is determined by simulated screening test.Through the secondary development of the software,the compactness of the track bed model can reach the standard of the real ballast bed.The problem that the discrete element model does not match the real situation is solved.On the basis of this discrete element model,the discrete element models of dirty ballast bed,mud-emerging ballast bed and harden ballast bed are created by modifying the particle gradation and related parameters.Combined with the relevant research contents of the ballast cleaning machine and the ballast bed,through the coupling of EDEM software and Recur Dyn software,the excavation process of excavation chain is simulated,and the movement law of ballast during this process is clarified.The stress of the excavation chain during the simulation is consistent with the result obtained by the empirical calculation formula.By setting up different control simulation experiments,the influence of each excavation parameter on the excavator of the ballast cleaning machine is analyzed.For general dirty ballast bed,increasing the chain speed can reduce the excavation resistance,but it has little effect on the excavation resistance fluctuations;the force of the excavation chain will periodically fluctuate with the movement of the ballast cleaning machine;increasing the excavation depth will increase the excavation resistance,but it will reduce the excavation resistance fluctuations.By discussing the excavation principle of the excavation chain,the article points out that the calculation of the excavation resistance of the excavation chain should be based on the impact principle rather than the cutting principle.In view of the above,the empirical calculation formula of the original excavation resistance is revised and supplemented,and the calculation formula of the average fluctuation amplitude of excavation resistance is proposed.By analyzing the difference between the stress and vibration of the excavation chain of the excavator under the condition of different deterioration of the ballast bed,and comparing it with the general dirty ballast bed,it is found that the excavation chain has the largest excavation resistance and the greatest impact during the operation of the harden ballast bed.This paper also analyzes the wear and strength of the excavation chain operating under harden ballast bed conditions.It proves that the life and strength of the excavation chain meet the requirements.This research provides a theoretical basis for the research of the ballast bed cleaning and excavation process and also provides a simulation test method for the optimization and improvement of the ballast cleaning machine and other railway maintenance machinery.