Interior Noise Prediction of Metro Train in a Tunnel Caused by Wheel/Rail Rolling

Metro running causes wheel/rail rolling radiation noise and reflects multiple times between the tunnel wall and the car body. Reverberation in a tunnel increases the interior noise and reduces riding comfort. A statistical energy analysis (SEA) model for a metro train in a tunnel is proposed to predict interior noise and improve ride comfort. The model considers the acoustic excitation caused by wheel/rail rolling, the damping/coupling loss factors, reverberation time in the tunnel/coach, and the equivalent panels. The results show that the error between the simulation and the measured is 3-6 dB; the SEA model is available. The mechanical wave of symmetrical loading may cancel out on the plane of symmetry. At low frequencies, the difference between the internal and external noise is slight (10 dBA), the transmission is robust, and the sound insulation of the car body is weak. In contrast, at high frequencies, the difference is significant (25 dBA). The tunnel reverberation effect increases the sound pressure inside the car by 8-12 dBA than the open-line, and the reverberation will reduce the spatial distribution gradient of the interior noise. Applying noise control treatment on the tunnel's inner wall can reduce the noise by 5-10 dBA.