Analysis Of Vertical Vibration Property Of Broad-Gauge Electric Locomotive-Track-Subgrade Coupled System

In the process of rolling stock driving,when the frequency excited by the wheels of the locomotive is close to the natural vibration frequency of the roadbed,the roadbed resonance phenomenon will occur,which will damage the roadbed.This phenomenon has promoted the researchers to begin to understand the roadbed dynamics research.The main content of subgrade dynamics research is the dynamic characteristics of subgrade under repeated wheel load（low-frequency vibration conditions）.Because the vibration frequency of the subgrade itself is relatively low,and the high-frequency vibration excited between the wheelset and the rail is relatively small for the subgrade system itself,the vibration analysis of the subgrade can be carried out with a relatively flexible simulation method.Under normal circumstances,under the premise of determining the quasi-static force between the wheel and rail and the excitation frequency,the establishment of the coupled vibration model of the wheel and rail system may not be considered.With the in-depth development of modern computer technology,it is possible to apply the coupled large-scale system model between vehicles,tracks and subgrades to subgrade dynamics.Therefore,the vertical dynamics study of the entire coupling system of broad-gauge electric locomotive-track-subgrade not only provides guarantee for the safe driving of vehicles,but also reduces the investment and construction costs and maintenance expenditures of rail transit.The main aspects studied in this paper are as follows:Taking the export-type C₀-C₀axle wide-gauge electric locomotive as the research object,by building a broad-gauge electric locomotive-track-subgrade analysis model in ABAQUS,the system includes:broad-gauge electric locomotive,track system,track bed,and subgrade.According to the basic idea of the vehicle-track-subgrade coupling system,the broad-gauge electric locomotive,track system,track bed,and subgrade are respectively established;the wheel-rail interaction system establishes a coupling mechanism between the wheel and rail according to the Hertz nonlinear contact theory;according to the basic assumptions proposed by Winkler foundation model,the corresponding foundation model is established.The types of track irregularities and various typical track spectra are introduced.In this paper,the high and low irregularities in the American rail spectrum AAR6 are used as the track excitation,and the mutual conversion program is written in MATLAB,and then the vertical coordinates of the top surface of the rail are modified in the INP file to achieve the effect of the rail surface irregularities.The numerical simulation method of ABAQUS is used for dynamic analysis to study the vertical behavior of the coupled system under a variety of different locomotive parameters and track parameters（locomotive speed,car body mass,sleeper spacing,vertical stiffness of fasteners,and track bed thickness）.To the dynamic response.Establish the track,sleeper,and track bed sub-analysis models in ABAQUS,add axle loads at the corresponding positions of the six wheelsets,and study the effect of stiffness changes on the rail,sleeper,and track bed in three directions（transverse direction）by changing the vertical stiffness of the fasteners,Vertical,longitudinal)stress and displacement changes.