Research On Fault And Defect Simulation Experimental Platform For Vehicle-rail Coupling System

With the increase of the speed and load of railway vehicles in China,the impact between wheel and rail will increase and the defects of wheel and rail will increase.At the same time,the wheel-rail defects further increase the dynamic response between wheel and rail,resulting in increased vibration,affecting the quality of train operation and seriously endangering the safety of driving.Therefore,the dynamic identification of wheel and track defects based on the dynamic response of vehicle and track is very necessary,and the simulation experiment of wheel-rail defect dynamic detection is of great significance for verifying the detection device and algorithm.Based on vehicle-track coupling vehicle and rail common defects in system simulation as the research object,this paper designs a fault defect simulation experimental platform based on the vehicle-track coupling dynamics model,which is used to simulate the defects of wheels and tracks in the laboratory,and The dynamic response detection experiment of wheel sets and rails under working conditions with wheel-rail defects.The main research content includes the following aspects:Firstly,the design scheme of the mechanical structure of the wheel-rail defect experimental platform is proposed,which simulates the actual wheel-rail operation and the actual wheel-rail defect characteristics.The roller-wheel system is used to simulate the actual train wheel-rail system.Vertical wheel load device is designed to simulate the actual wheel vertical load.The experimental platform uses hydraulic cylinder to drive the support beam of the roller to produce random track irregularities.The vertical quasi-sinusoidal displacement of the roller is designed to simulate the corrugation of the track;because the actual conditions of sleeper and ballast bed cannot be simulated under the roller,Therefore,according to the vehicle-track vertical model,the under-track situation is equivalent to a simulation of stiffness and damping.Secondly,the signal control and acquisition system of the experimental platform is designed.According to the principle of the control and acquisition system of the experimental platform,the physical parameters of the control and acquisition are determined.The control system of the experimental platform mainly consists of three parts: hydraulic system,pneumatic system,and motors.The actuators of the three systems are controlled by the industrial computer to send instructions to the PLC to realize the control of the hydraulic cylinder of the track irregularity generating device,the wheel vertical load device,the equivalent stiffness and damping under the rail,the running speed of the wheel-rail system and the frequency of the track corrugation.The signal acquisition system uses displacement sensor,load sensor,high-speed proximity switches,pressure sensors,and vibration acceleration sensors to realize the experimental platform roller displacement,wheel vertical load,roller and eccentric wheel speed,equivalent stiffness and damping under the rail,as well as the measurement of the vibration response of the wheel and the roller.The collected information is transmitted to the industrial computer through the data acquisition card to detect and control the experimental conditions.The track irregularity simulation system in the control system is a closed-loop control.According to the realization scheme of the track irregularity system,the irregularity hydraulic control system is designed.The simulation model of the hydraulic system is established by using the Simscape tool module,and the function of the hydraulic system and the control accuracy of the simulation of the track irregularity are verified.Finally,the dynamic detection experiments of the wheel and track defects were carried out on the experimental platform,and the vibration accelerations of the wheel and roller were obtained under the defects such as track corrugation,track irregularity and wheel tread flat.Through the time-frequency analysis of the dynamic response of wheel and rail,the experimental results show that the vibration signals of the wheel and roller have a large value at the frequency of the corrugation.When there is a wheel tread flat,the vibration signal will produce obvious periodic amplitude,and the amplitude appears at integer multiples of wheel frequency.The equivalent stiffness experiment shows that the vibration accelerations of both wheels and roller increase in the full frequency domain with the increase of the stiffness.With the increase of equivalent damping,the vibration of wheel and roller decreases obviously due to the damping effect.The irregularities simulated by the experimental platform increase the vibration of wheel and roller in the full frequency domain.Therefore,the dynamic response of wheel and track due to defects can be detected on the experimental platform by using the characteristics of wheel and rail defects.In this paper,a simulation experimental platform is designed to simulate the defects of wheel and track and carry out dynamic detection experiments under various defects,which provides laboratory data for the dynamic detection experiment of wheel and rail defects.