| In recent years, our country’s high-speed train got rapid development, however with the improving of the speed of the train, the interior noise and vibration had increased. It had serious effects on the ride comfort of passengers and at the same time it exacerbated wear of the mechanical parts of the train, which reduced its service life and even threatened the safety of the train. All of these to some extent restricted the development of the high speed train. So with the support of the National Science Foundation project-Active control study on multidimensional vibration of precision equipment based on flexible metamorphic mechanism (51275275) and Shandong Young Scientist Research Award Fund-Study on active vibration control of precision equipment based on flexible metamorphic mechanism (BS2010ZZ006), we made the analysis and prediction of the low frequency noise inside the train based on a type of high-speed train, which had a realistic significance. This paper carried out the following aspects of research work:Firstly, the domestic and foreign achievements of analysis and control of interior noise and vibration were reviewed. And the harmfulness, the mechanism, the route of transmission and the control methods of the low frequency interior noise were expounded. Also we introduced the evaluation criteria of the interior noise of the train.Secondly, we made the modal analyses of the 7m long white body platform in the lab because of the complexity and difficultly of experiment of high-speed train. By compared the modal inherent frequency and formation of the simulation and test, we got a precise and efficient model. Then we had known the high-speed train’s structure characteristics and mastered the technology to establish an accurate and effective whole train model, which was useful for the analysis of the whole car interior low-frequency noise.Then, for a large number of periodic corrugated sandwich panels exist in the high-speed train, the method of making the periodically corrugated board equivalent to anisotropic material plate was inferred. The equivalent method was confirmed feasibility by comparing the results of the modal and sound insulation of the periodically corrugated board and equivalent plate using simulation technology combined with laboratory tests. This approach not only greatly simplified the modeling of high-speed trains and reduced the computation time of analysis, but also provided a convenient for structural optimization.Subsequently, we made analysis of structural characteristics of the entire high-speed train carriage, and used the equivalent ways to build an efficient and accurate finite element model of the train carriage. The modal analysis of the train with and without interior material was made to make sure the influence of the interior material on modal of the entire train carriage. At the same time, the model of the acoustic cavity was established and we discussed the resonance situation of structure and acoustic.Finally, we used the finite element method combined the incentive which was got by the experiment to analyze the structural vibration response when the train was in moving. While the assessment of sound field in the car was made using the boundary element method. After contrasted the sound pressure response of simulation with experiment in the 4 standard points, we got a model which was able to effectively predict the interior noise pressure. ATV method was used to make the contribution analyzed of each panels of train, and the factors of contribution in the main noise frequencies was given. Then some guidance of body modification to optimize the acoustic structure were provided... |
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