Research On The Mathematical Model Of Three-point Lateral Jacking Of Turnout Rail

Turnout is an important part of railway track equipment,and it is an indispensable key equipment for train commutation.With the continuous increase of mileage and speed of high-speed railways in China,higher requirements have been placed on the quality and output of turnout equipment.It is necessary to straighten the bending defects of the original rail pieces,and to bend the rail pieces at the corresponding positions,which is collectively referred to as the turnout rail piece top adjustment process.The top adjustment accuracy determines the smoothness and reliability of train operation.At present,Turnout rail parts mainly rely on manual experience to determine the top adjustment process parameters,and manually operate the press to perform the top adjustment.The top adjustment accuracy is unstable,the production efficiency is low,and the labor intensity is large.Therefore,this article takes turnout basic rails as the research object.Based on the theory of elastoplastic mechanics and pressure straightening,the load-deflection relationship in the process of pressure adjustment of rails is analyzed.The combination of "theoretical analysis-finite element simulation-experimental verification" is used Method to study the pressure adjustment of turnout rails.The main research contents are as follows:(1)The tensile test of U71 Mn rail steel at room temperature was performed to obtain the true stress-strain data of the material,and a linear reinforced stress-strain model for the material was established to provide material parameters and models for the theoretical calculation and finite element analysis of the three-point pressure adjustment of turnout rails.(2)Analyze the relationship curve of bending moment,plastic-bending ratio and spring area ratio of the horizontal top adjustment process of basic rails of 50 kg / m,60 kg / m and 75 kg / m turnouts,and calibrate the minimum spring area ratio and the maximum plastic-bending ratio.The load-deflection theoretical mathematical model of the three types of rails in the lateral adjustment process under different support distances was verified,and the accuracy of the theoretical mathematical model was verified by ABAQUS beam element finite element analysis.(3)A finite element simulation model of the ABAQUS turnout basic rail set-up process was established based on the actual top-adjustment process at the industrial site.The elastoplastic stress distribution of the rail during the set-up process was analyzed,and it was proved that the stress distribution during the rail set-up process was a typical bending stress distribution.Based on the finite element simulation data,the load-deflection model of the rail fitting adjustment process was established,and the theoretical calculation mathematical model was modified.Based on the revised load-deflection model,the top bending stroke of the straight rail piece and the straightening stroke of the curved rail were adjusted.Prediction analysis,and straightening experiments based on rail examples verify the accuracy of the correction factor selection in this paper.