| The rapid development of high-speed railway has made the railway noise and vibration a much more serious problem. Bridge noise, as part of railway noise, is'second radiated'noise induced by trains. Although bridge noise which belongs to low frequency noise (<100Hz) in the frequency range occupies few percentage of the total railway noise, it is still necessary to study the generation mechanism and effective noise reduction measures for the hazard of low frequency noise and lack of systematic countermeasures.This paper intends to investigate the low frequency noise radiated from a commonly used type of simple supported concrete girder induced by high-speed trains. The major contents of this paper show as follows:1) A brief literature review is done to introduce the research status and methods on railway noise. Then the numerical analysis methods such as finite element method (FEM), boundary element method (BEM) and statistical energy analysis (SEA) for sound radiation due to structure vibration are summarized and compared.2) A method combining Train-Track-Bridge (TTB) interactive theory with BEM is proposed to solve the traffic induced low frequency noise from bridge structures. Boundary integration equation based on Green identity is established for the calculation of unbounded acoustic region. Basic assumption and calculation process of the proposed method combining TTB and BEM is raised after a brief introduction to the analysis method of TTB interactive theory.3) A TTB interactive analysis software, BDAP 2.0 (Bridge Dynamic Analysis Program Version 2.0) developed by SWJTU is applied to investigate the dynamic characteristic and traffic induced response of the bridge. Then the sound pressure level(SPL) of the surrounding environment is estimated by a commercial BEM software.4) Parameter study is made to find out the qualitative relationship between bridge noise and possible factors such as sound barriers, train speed, pier height, and ground reflection. |
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