The effects of rail weld impacts on wheel structural vibration

Train wheel as a continuous system has structural vibrations. The source of excitation is usually the railway track irregularities. These irregularities can be classified as short and long pitch ones. Short-pitch irregularities are corrugation, local defects like rail welds and spalling, and superstructure defects such as void sleepers. Due to the impact nature of short-pitch irregularities, it is expected that these impacts affect the wheel structure and its vibration (at the instant of excitation). In order to investigate this issue, wheel structural vibration is investigated using axle box acceleration measurement. With the help of finite element method, the natural frequencies of a wheelset were extracted compared with the results obtained from a field test. Tehran Metro was selected for this purpose. The test results were analyzed by Fourier transform and natural frequencies and their amplitude over time were extracted and discussed. It was concluded that the first five structural modes of the wheel, predominate in the wheelset structural vibration. Also, Rail weld impacts and corrugation has the greatest effect on the wheelset structural vibration.

Keywords:

wheelset structural vibration , FEM , field test , Tehran metro , axle box acceleration.