钢轨波磨对地铁车内噪声影响及其控制试验研究

随着轨道交通快速发展,车内噪声已成为列车运行中一个重要问题。为了研究某地铁车内噪声超标的原因,对该线路钢轨打磨前后车内噪声进行测试,分别使用A计权和响度来分析其声学特性,并比较A计权和响度评价车内降噪效果的差异。结果表明:波长0.025 6～0.051 2 m波磨是地铁车内噪声超标的主要原因,通过清除波长0.025 6～0.051 2 m波磨,6个测点声压级明显降低。通过A计权分析可知,钢轨打磨对前端和后端车厢降噪效果较为明显,而对中部车厢降噪效果不如前者。通过响度分析可知,列车前端和后端车厢的4个测点车内噪声总响度降低,而在中部车厢的2个测点总响度略有增大。评价噪声主观感觉大小的A计权低估了中部车厢100～300 Hz频率的噪声影响,而响度作为反映人耳对声音强弱感觉的心理声学参数,能够更为准确地评价低频车内噪声对人耳的影响。

Experimental Study on Influence and Control of Rail Corrugation on Interior Noise of Metro Cars

With the rapid development of rail transit, interior noise has become a serious issue in trains operation. In order to understand the reason why the noise in a metro car exceeds the standard, the noise inside metro cars before and after grinding on a Metro line are tested, and the A-weighted and loudness are used respectively to analyze the acoustic characteristics and compares the difference between A-weighted and loudness evaluation of noise control in railway vehicles. The results show: wavelength 0.025 6～0.051 2 m rail corrugation is the main reason for excessive noise in the metro car, and 6 measuring points sound pressure level significantly reduced by grinding wavelength 0.025 6～0.051 2 m rail corrugation. By A weighting analysis shows, rail grinding on the front and rear compartment noise reduction effect is more obvious, for the central car, noise reduction effect is not as good as the former. However, by the analysis of loudness, the total loudness of the 4 measuring points inside the front and rear compartments is reduced, but the total loudness of the 2 measuring points in the middle compartment slightly increased. The A-weighted assessment of subjective perception of noise underestimated the noise impact of 100～300 Hz frequencies in the center car, however, the acoustical parameters of the loudness as the response to the strong and weak sense of the sound in the human ear, can more accurately evaluate the impact of low-frequency noise on the human ear.