Detection Of Wheel Polygon By Piezoelectric Accelerator Based On Numerical Simulation

With the rapid development of high-speed railway,the running speed and axle weight of trains continue to increase.wheel polygon wear has become a difficult problem in high-speed railway EMUs.Polygonal wheels not only cause an increase in wheel load between the wheel and rail,but severe shock vibrations also shorten the service life of the track-vehicle components,which may affect the running quality,safety and operating costs.Based on the vibration response of the rail caused by the wheel polygons under high-speed conditions.A detection method based on rail vibration acceleration measurement by piezoelectric accelerator is proposed.The piezoelectric acceleration sensor is designed.The dynamic characteristics and the feasibility of the detection method are verified by simulation,which can provide theoretical guidance for practical engineering applications.The main research work includes:(1)The Finite Element Model(FEM)of the high-speed railway slab track is established by the software ANSYS.The dynamic simulation model of vehicle track coupling system is established in Universal Mechanism(UM)environment to solve the wheel-rail interaction force.Then they are input into the slab track model in an array form.Based on the vibration response characteristics of the rail due to wheel polygons on high speed condition,the layout of the piezoelectric accelerators for measurement of rail accelation is determined.(2)According to the applicable conditions of various piezoelectric materials and structure types in elements,a new piezoelectric acceleration sensor for rail vibration acceleration measurement is designed.The FEM of piezoelectric acceleration sensor is established to optimize its structure parameters,and to analyze the dynamic sensing performance of piezoelectric accelerator,Simulation results note that the piezoelectric acceleration sensor designed can meet the requirements for wheel polygons detection.(3)The FEM coupling model between piezoelectric acceleration sensor andtrack structure is established.The relationship between the output voltages of piezoelectric acceleration sensor and wheel polygonal wear parameters,such as wear depth,harmonic order and running speed is established.The feasibility and rationality of the presented method is verified.The study can provide theoretical guidance for field experiments.