Analysis on fracture causes of SKL15 fastener clips in high-speed railway

Abstract:

To analyze the reasons for the fracture of fastener clips in high-speed railway operating lines, SKL15 clips were studied as the object using a method of combining field test and simulation analysis. First, an on-site investigation of rail corrugation and vibration response characteristics of clips was performed. Then, a finite element model of the fastening system was established. The modal characteristics of the clips in their free and assembly states were analyzed, and a harmonic response analysis was carried out based on the modal superposition method. The reliability of the model was proved by comparing the field test results with the simulation results. Finally, in combination with the test results and the railway operation situation, the fracture causes of the fastener clips were analyzed, and remedial measures were put forward. Results showed that the main reason for the fracture of clips was that the load frequency excited when the train passed through the corrugation section with a significant wavelength of 50-60 mm at a speed of 120 km/h was very close to the modal frequency (550–650 Hz) of the clips in the assembly state, which caused the clips to have a strong resonance effect and resulted in the significant increase in the stress at the heel end of the clips, and eventually, fatigue damage. As a result, some solutions were put forward, such as rail grinding, train speed adjustment, and clip structural optimization.