Research On Dynamic Model Of MT-2 Draft Gear Based On Impact Test

With the increasing demand for coal,iron ore and other bulk goods,it has become an important way to improve the efficiency of railway transportation by increasing the axle load of vehicles and expanding the marshalling of vehicles.However,the development of heavy-duty trucks will inevitably lead to a significant increase in the longitudinal impulse of trains,which in turn will increase the coupler force and cause problems such as wear the vehicle structure?broken hooks and derailment.Therefore,solving the problem of longitudinal dynamic performance of the train has become a key factor in the development of heavy-duty transportation.As an important part of the coupler buffer device,the research on buffer's performance has become a hot spot in the longitudinal dynamics research.Study the internal structure of buffer,analyze the impedance characteristic curve,establish buffer mechanical model,establish dynamic differential equation based on the actual test process,and the dynamic simulation analysis of buffer is carried out by using programming software,which provides an effective method for improving the performance of buffer in the future.This paper describes the development of buffer at home and abroad,and summarizes the development of the longitudinal dynamics and buffer simulation research.The working principle,structural characteristics,and impedance characteristics of the MT-2 buffer are described in detail.The sixth-order polynomial fitting method was used to select the most appropriate one-time test data from the three test data at the same speed level.Then,the experimental data is fitted to the sixth order,and the three points with the largest changes in the curvature of the fitted curve are obtained,and the initial point of the fitted curve and the peak point of the test data are obtained.And the rebound point determined by the slope is used as the six feature points on the MT-2 buffer characteristic curve.Using interpolation function to interpolate the characteristic points of the buffer to obtain the relationship between the impedance force and the compression amount,and combined with the relationship between velocity and impedance force,a buffer gridding model between impedance and velocity and compression is obtained.The differential equation of one-to-one truck impact dynamics is established.The displacement,velocity and acceleration of the impact vehicle and the impact vehicle are obtained by using the Newton-Leibniz formula and the simple iterative method by using the buffer gridding model.Using MATLAB to compile vehicle impact test numerical simulation program,when the relative velocity of the two vehicles is less than 10-4km/h,the program stops and the simulation curve of the output impedance force changes with the displacement of buffer is compared with the test data.Comparing the simulated curves with the test curves,the relative error of the test data and the simulation data is less than 4.39%in the maximum compression displacement,and the relative error of the coupler force of the buffer is less than 4.37%when the maximum compression displacement occurs.lt is proved that using the maximum curvature point of the fitting curve as the turning point of the characteristic curve of the buffer and the linear reduction of the compression speed is feasible,which provides a good technical support for the research,design and application of the buffers in the future.