Research On Dynamic Mechanical Characteristics In The Operating Process Of Dynamic Track Stabilizer

The ballasted track structure,which has characteristics of good pressure dispersion,vibration dispersion,resistance to vertical and lateral movement and easing the impact,is the main form of railway track.After overhaul and maintenance,the density of ballast bed,the lateral resistance and stability of the railway line are of bad status.The operation of dynamic track stabilizer can improve the lateral resistance and the overall stability of the line which offers a condition for enhance the carrying capacity and the running speed.The dynamic track stabilizer is an important equipment of railway line to repair,upgrade a railway line and construct a new railway.Therefore,it is of great significance to study the operation process of the dynamic track stabilizer,which will improve the accuracy and efficiency of operations,the quality of the track and accelerate the development of high-speed and heavy load railway.The study of vehicle track coupling dynamics is gradually mature,but the research on the coupling dynamics in the operation of large-scale railway maintenance equipment is rarely reported.The systematic research on the performance and effect of the operation of WD-320 dynamic track stabilizer is lack and the setting of operation parameters mostly comes from the experience of overseas.This research takes the WD-320 dynamic track stabilizer as the research object,carries out scientific dynamic analysis and research on operation process.The establishment of coupling model and numerical simulation,the verification of the simulation results and the experimental results,the changing rules of ballast bed stiffness and damping with time of operation process,effect of operation parameters on the track quality state,prediction of the lateral resistance of single sleeper after operation,the best matching parameters of operation are all covered in this research.The specific research contents are as follows.(1)Based on theory of vehicle track coupling dynamics,with the stability module added,the vertical and lateral spatial vehicle track coupling model of dynamic track stabilizer is established.The vehicle track coupling dynamics simulation analysis of dynamic track stabilizer is analyzed using MATLAB software.In this research,the interacting principle in the process of dynamic track stabilizer is analyzed.The vibration models of vehicle system and track system under running and operating conditions are studied in detail.The excitation of the track irregularity and the stabilizing device are determined.The simulation data obtained from the simulation analysis system are compared with the experimental data,and the validity results are shown.The dynamic response analysis is carried out by using the experimental data.(2)Based on the discrete element method,this research simulates the operation process of dynamic track stabilizer.The changing laws of supporting stiffness and damping of the sleeper and ballast subsidence in the operation process are studied.A function models of variable stiffness,variable damping and cumulative settlement with time are established.Then the ballast stiffness and damping and cumulative subsidence data of every time points during the operation process are extracted by EDEM simulation analysis.The functional models of the ballast stiffness,damping and cumulative subsidence are modeled by fitting,and verified effective.The functional model is beneficial to optimize the actual operation parameters and improve the accuracy of the numerical simulation.(3)Based on mathematical statistic method,the effects of different operation parameters to the quality state of ballast bed are studied with the analysis of testing data.And the optimal operation parameters of the single factor and the way to improve the carrying capacity of the railway line are found out.This research expounds the index of the ballast bed quality control.The lateral resistance can be roughly evaluated by the quality state of ballast bed after the operation process.The lateral resistance value of single sleeper under different operation parameters are extracted through the field test,and the systematic analysis and comparison are carried out.The different ballast state has no significant effect on promoting the rate of the sleeper lateral resistance before and after the operation process,except the extreme state of ballast;the vibration frequency of 18-30Hz is the effective operation frequency range of the dynamic track stabilizer which can effectively improve the quality state of ballast bed,in which 28Hz is the optimal operation frequency;the pressure of 50-80bar is the effective operation pressure range of the dynamic track stabilizer which can effectively improve the quality state of ballast bed,in which 50bar is the optimal operation pressure;influence of different velocities on the quality state of ballast bed is not obvious.A ballasted track multi constraint device is developed which can enhance the overall carrying capacity of the railway line and increase the speed of passage.(4)Based on the theory of multiple nonlinear regression,the prediction model of optimal operation parameters of the operation process is established.The single sleeper's lateral resistance after operation with different parameters which extracted from field tests is analyzed.Correlations between hardening coefficient of ballast bed,operation speed,pressure,vibration frequency,the sleeper lateral displacement,the single sleeper lateral resistance before operation and the sleeper lateral resistance after operation are analyzed;the possibility of establishing a multivariate linear regression prediction model that the lateral resistance of single sleeper changes with the operation parameters is discussed.By using the method of nonlinear relationship into a linear relationship,multivariate nonlinear regression models are established for quadratic,cubic and quartic.After the analysis and comparison,the quartic regression model is modified.Finally,with the multifactor tests and test data verification,the quartic regression models of six factors is of good model to match the practical situation.This model can be used to measure the performance of the operation,and to find the best combination of operation parameters.In this research,the operation process of the dynamic track stabilizer is simulated and tested combining with the system dynamics,discrete element method,mathematical statistics,regression theory,etc.Systematic analysis on the effects of different operation parameters to the quality state of ballast bed is done;the functional parameter model and the optimal parameter prediction model are proposed,which can provide a reference for the optimization of operation process of the dynamic track stabilizer in the practical application.