Study on the measurement of buckle pressure of rail elastic strip fastener based on modal method and ultrasonic method

The railway elastic strip fastener system is heavily used in the laying of seamless lines, where the buckle pressure of elastic strip fasteners is an important part of railway safety inspection. This paper investigates and analyzes the eigenfrequency measurement method of the buckle pressure of the rail elastic strip fastener based on the modal theory, and analyzes the relationship between the first two orders of characteristic frequency and the buckle pressure using COMSOL Multiphysics simulation. Meanwhile, based on the relationship between the axial load of the spiral stud and the buckle pressure of the sling, the buckle pressure of the railway fastener can also be obtained by measuring the propagation time of the transverse and longitudinal waves in the spiral stud. Through experiments, the second-order characteristic frequency of the elastic strip vibration, the relationship between the buckle pressure and the preload torque of the fastener, and the relationship between the horizontal and vertical wave acoustic time difference and the buckle pressure of the elastic strip are measured, which provides an effective solution for accurately measuring the buckle pressure of the elastic strip.