Sfm05 Type Moving Subway Car Noise Prediction And Acoustic Contribution Analysis

Subway noise has affected the normal life of people. To restrict subway noise in certain scope, related organizations have established mandatory acceptance standard of subway noise. To accord with standard level for subway noise, thorough researches were carried out about noise sources, acoustical loads and the internal and external noise forecast method for subway motor-vehicle (M vehicle) at running and static conditions.The acoustical boundary element model was established for subway M vehicle, the acoustical loads of M vehicle at static conditions were put on the acoustical boundary element model, the sound presses level (SPL) was obtained in and outside M vehicle at static conditions. In M vehicle the A sound levels changes in the range of 60.87-69.04 dBA, outside M vehicle in the range of 66.78-77.38 dBA. From the results of the acoustical contribution analysis of noise source, the main source is air-condition at roof at static conditions for M vehicle. To reduce the noise of M vehicle at static conditions, the noise from air-condition must be controlled.Wheel rail noise and the panel vibration of railway carriage are the important sources for M vehicle noise. The vehicle-track coupling dynamics model was established, and the loads caused by track irregularities were calculated for the fulcrum places of railway carriage. By harmonic analysis the panel vibrations of railway carriage were obtained. Using statistical energy analysis, wheel-rail vibration noise was forecast. Taking wheel-rail noise, the panel vibration of railway carriage and other noise sources as acoustical load, the sound presses level was obtained in and outside M vehicle at running conditions. In M vehicle the A sound levels changes in the range of 71.46-76.28BA, outside M vehicle in the range of 78.05-85.61dBA. From the results of the acoustical contribution analysis of noise source, the main source is wheel rail and the panel vibration at running conditions. At running conditions, to reduce the noise in M vehicle, the panel vibration must be controlled. To reduce the noise outside M vehicle, the noises from wheel and rail must be controlled.The characteristic of acoustical contribution degree was discussed, the acoustical contribution of panel were calculated for interior noise, the results show that the acoustical contribution of first, second, fourth, fifth panel at floor are greatest for interior noise, after damping materials were covered on the first, second, fourth, fifth panel at floor, the noise in M vehicle reduces 1.3 dBA.