Correlation between Rail Vibration and Sound Radiation Using a Hammer Impact

Abstract

When the track structure is subject to certain excitation, the vibration characteristics and sound radiation characteristics will show certain correlation with each other. However, the study on finding the direct relationship between rail vibration and radiated sound is very limited. In this paper, the correlation between the rail vibration and radiated sound pressure under a hammer impact was investigated with a full-scale track slab. The rail acceleration, rail surface sound pressure and radiated sound pressure nearby at the rail web and rail foot were measured and analyzed in frequency domain. The transfer function, coherence function were obtained to reveal the relevance between each pair of input and output signals. Finally, by choosing rail vibration acceleration and surface sound pressure as input excitation and choosing the surface sound pressure and the sound pressure in near field as output response successively, the transfer function and the transmission loss for each pair of input and output were analyzed and compared to reveal the signal transmission in different frequency ranges.