多跨简支梁桥低频噪声预测及空间分布研究

PREDICTION AND SPATIAL DISTRIBUTION OF LOW-FREQUENCY NOISE RADIATED FROM THE MULTI-SPAN BRIDGE

  • 摘要: 现有的桥梁噪声预测方法大多仅考虑一跨桥梁的噪声辐射而忽略了相邻跨桥梁的影响。提出了预测多跨桥梁低频噪声的方法:首先,通过车辆-轨道-桥梁动力相互作用分析计算了列车通过多跨桥时的桥梁响应;然后,采用2.5维边界元方法获得多跨桥梁的声模态传递向量;最后结合桥梁动力响应和声模态传递向量求得多跨桥梁的总辐射噪声。以某轨道交通U梁为研究对象,对比了采用多跨桥梁模型、单跨桥梁模型的计算声压结果的异同,并与实测值进行比较,明确了在预测远场噪声时必须采用多跨桥梁计算模型。研究表明,多跨桥梁的辐射噪声沿桥梁纵向分布较为均匀,在现场实测时可选取任意横断面位置进行噪声测试。

     

    Abstract: A single-span bridge model was usually used in the bridge noise simulation in most of the existing literature, which ignores the noise radiated from adjacent spans. A prediction method is proposed to predict the multi-span bridge noise in this study. First, the vibrations of the multi-span bridge are calculated from the vehicle-track-bridge interaction analysis. Then, the modal acoustic transfer vectors (MATVs) of the multi-span bridge are obtained using the 2.5 dimensional (2.5D) boundary element method. Finally, the multi-span bridge noise can be derived combing the bridge vibration and the associated MATVs. The simulated sound pressures radiated from the U-shaped girder obtained from the multi-span bridge model and single-span model are compared with the measurements, and the research shows the multi-span bridge model should be used in the far field noise prediction. The investigation of the spatial distribution of the multi-span bridge noise shows the bridge noise almost distribute uniformly along the longitudinal direction. Thus, an arbitrary section perpendicular to the bridge can be chosen in the field test.

     

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