轨道交通混凝土桥梁中低频噪声预测方法

Prediction of Low-to-medium Frequency Structure-borne Noise Radiated from Rail Transit Concrete Bridges

提出预测轨道交通桥梁和钢轨中低频噪声的精细化模型:首先,建立3D桥梁和钢轨有限元模型;然后,结合3D车辆-轨道-桥梁耦合振动模型和2.5D声学无限元模型计算列车通过时的桥梁噪声和钢轨噪声。以上海轨道交通某混凝土U梁为研究对象,对桥梁辐射噪声和钢轨辐射噪声的频谱特性和空间分布规律进行了研究,并通过实测对比验证数值计算方法的精度。研究表明:桥梁结构噪声主要在U梁下方的空间起主导作用,而钢轨噪声在U梁上方的贡献更大;在距离轨道交通中心线20m处,两者的声压值基本相当,在噪声预测时桥梁噪声与钢轨噪声的贡献均需考虑。

A refined prediction model was proposed to predict the low-to-medium frequency noise in bridges and rails in urban rail transit system.First,a three dimensional（3 D）finite element model of the bridge and rail was developed,and the bridge noise and rail noise when the trains passed were calculated by combining the traintrack-bridge interaction analysis and 2.5 dimensional（2.5 D）acoustic model.Based on U-shaped girder of the rail transit system in Shanghai,the spectral characteristics and the spatial distribution of the rail and bridge noises were investigated.The accuracy of the numerical calculation method was verified by the measured comparison.The results show that the bridge structure-borne noise is dominant in the space beneath the U-shaped girder while the rail noise constitutes a greater part in the space above the U-shaped girder.The bridge noise is comparable with the rail noise at the distance of 20 maway from the track center.Thus,the contribution of both the bridge noise and rail noise should be considered in the noise prediction.