Design And Study On The New Type Of Fatigue Testing Machine For Railway Spring Bar

The fatigue testing machine is a new type of fatigue testing machine which was developed independently by our group.The machine can be used at testing the fatigue test of all kinds of the railway standard projectiles.This paper introduced the working principle of the testing machine,and the structure of the railway spring bar fatigue testing machine was being designed.And then the mathematical model of the fatigue system of the fatigue testing machine was established and the numerical solution was carried out,and the appropriate parts would be selected.The three-dimensional solid model of the railway train fatigue testing machine could be drawn by using Creo4.0.The finite element analysis and kinematics simulation were carried out to verify the rationality and reliability of the new structure.The friction and lubrication characteristics of the support position were analyzed according to the location of friction and wear.This paper mainly studies from the following aspects:Firstly,the structure design of the new type of fatigue testing machine for railway spring bar was selected according to the test requirements of this subject.The appropriate parts and components were selected to establish the three-dimensional solid model of the fatigue testing machine in Creo4.0.It mainly included the structure design of the preloading force device and the displacement loading device,and designed the control system of the new type of fatigue testing machine for railway spring bar.Secondly,this paper established the kinematic model of the new type of fatigue testing machine for railway spring bar,and analyzed the kinematics of the eccentric wheel.According to the kinematics analysis results,the numerical simulation was carried out in MATLAB,and the variation of displacement,velocity and accelerationof the eccentric rod with the influence parameters could be obtained,thus providing an effective reference for the design of the main moving parts.Thirdly,ANSYS Workbench17.0 and Creo4.0 were used in key components for finite element analysis of the new type of fatigue testing machine for railway spring bar in this paper.The value force of the test condition could be obtained according to the analysis of the fixture force on the basis of the test standard of the spring bar.At the same time,the static analysis of the fixture system was carried out to verify the rationality of the design.The modal analysis of the whole three-dimensional model of the fixture system was being used to avoid the occurrence of resonance in the test process and ensure the safety and reliability of the testing process.The optimal solution of the large and small eccentric wheel were obtained by the optimal design of the eccentric wheel mechanism.The optimal linear model of the linear buckling of the long rod could be obtained by the optimization of the linear buckling analysis of the long Linear Buckling module and the Response module data.Fourthly,the friction and lubrication characteristics of the support position were analyzed according to the location of friction and wear,and the oil film thickness equation at the support position was deduced.At the same time,several major influence factors of the oil film thickness could be obtained by numerical analysis.The main influence factors of the heat could be obtained through the analysis of friction and heat generation during lubrication.The main influence factors of the amount of oil were analyzed by deriving the equation of the required amount of oil.That provided an important theoretical reference for the design of deep groove ball bearings and the use of lubricating oil in the railway fatigue testing machine.Finally,the dynamic simulation of the new type of railway bar fatigue testing machine was carried out by ADAMS,and the motion law of the actuator was obtained to verify the correctness of the theoretical analysis.The prototype and the experimental study of the new type of railway bar fatigue testing machine were carried out,and the results of the experimental study were compared with the theoretical analysis and simulation results to verify the rationality of the design of the new type of fatigue testing machine for railway spring bar.