Impact of rail grinder vibration characteristics on grinding quality and alleviation measures

Periodic grinding marks generated during rail grinding can readily serve as excitation for the initiation of rail corrugation. To improve the rail surface roughness after rail grinding, an improvement of the grinding carriage frame was conducted based on the analysis of resonance characteristic. Vibration tests revealed that the vibrations were dominated by the grinding motor’s rotation at the frequency of 60 Hz, and there were significant vibration responses ranging from 59 to 63 Hz in the grinding carriage frame. Modal analysis further revealed that the longitudinal expansion and contraction of the primary longitudinal beams of the grinding carriage frame with natural frequency of 57.6 Hz and the rolling motion of the crossbeams with natural frequency of 60.3 Hz were exacerbated by the motor rotation at 60 Hz. From the perspective of avoiding resonance, a structural improvement of the frame was conducted, resulting in a notable reduction in motor vibration. The vibration jump-up of the improved structure from idle condition to grinding condition decreased by 66% compared to that before structural improvement. The rail roughness at the wavelength corresponding to the resonant frequency decreased from 19.8 dB before grinding to 15.3 dB after grinding, representing a reduction of 22.6%, and this enhanced grinding effect was 1.9 times that of the original structure. Therefore, the improved grinding carriage frame can significantly alleviate the impact of resonance, thereby reducing the fluctuations in grinding force during the process, and substantially enhancing the quality of rail grinding.