A study of the axle box ASD spectrum of high-speed rail vehicles based on field test measurements in China

Abstract

The axle box ASD (Acceleration Spectral Density) spectrum serves as the main resource of high frequency vibration for rail vehicles, which is usually taken as a critical load spectrum for the evaluation of vibration fatigue of rail vehicle sub-assemblies. However, the continuous in-service failures occurring in a plenty of rail vehicles invariably suggested a low reliability for the ASD defined in IEC 61373 standard for some scenarios. This paper thus investigated on the characteristics of axle box ASD spectrum through measurements acquired from a number of high speed rail vehicles in China, so as to develop a more realistic vibration spectrum for the considered operation condition. Firstly, a brief review for typical fatigue failures of rail vehicles was conducted to understand fatigue failure modes caused by the high frequency vibration of wheel/rail system. Subsequently, the definition of axle box ASD spectra in IEC 61373 was analyzed and further compared with the ASD spectra of axle box obtained from measurements to demonstrate the reliability of standard vibration level. The results suggest that the ASD spectrum given in IEC 61373 underestimates the vibration level in high frequency ranges, especially the frequency band above 500 Hz. Finally, a modified ASD spectrum profile of axle box considering the characteristic frequency bands of wheel/rail system was proposed to better representation of vibration characteristics of axle box, especially for those arising from the wheel/track vibration modes. This is expected to better characterize the vibration characteristics of axle box for rail vehicles, and improve the estimation accuracy of fatigue lifetime for the components subjected to the axle box vibration.