A STUDY ON THE SQUEAL NOISE FOR SUBWAY VEHICLES IN KOREA

초록

Railroad vehicles running in tight curves often generate intense, high-pitched squeal noise. This squeal has always been noticed as one of the most disturbing noise sources of railroad systems. The mechanism of noise in curves is not analyzed enough yet, but it is known that there are three types of models. The first is differential slip between inner and outer wheels on a solid axle. The second is rubbing of the wheel flanges against the rail. The third is lateral slip of the wheel tread across the rail head. In Korea, there are many subway lines with tight curves of radius less then 300R. In these curves, the curving noise level is very high and it is harmful to silent environment. In order to reduce the curving noise level, several ways are able to be considered. In this study, the low noise wheel and rail head/side lubrication were considered. We measured and compared the curving noise before and after treatment of squeal noise reduction method. The noise reduction effects were analyzed in magnitude and frequency. We also performed structural analysis to find out the frequency of the wheel and squeal noise. In conclusion, the frequency of squeal noise coincided with the frequency of wheel in axle direction. Rail head lubrication method and low noise wheel was effective for reducing the curving noise.