高速铁路钢桁结合梁桥结构噪声预测研究

Prediction of Structure-borne Noise of Composite Steel Truss Bridge of High-speed Railway

为了解高速铁路钢桥结构噪声辐射特性,基于车-线-桥空间耦合振动理论和统计能量分析原理,提出高速铁路钢桥结构噪声预测模型,对其辐射噪声空间分布规律和结构各部分声贡献量进行分析。该预测模型采用空间板梁混合有限元模型进行车-线-桥空间耦合振动分析,得到桥面板的振动速度时程,经FFT变换后得到频域内的结果,作为后续统计能量模型的输入。通过求解统计能量平衡方程,得到系统振动能量分布和传递结果,根据振动声辐射理论,求得桥梁结构噪声。对64m钢桁结合梁的分析结果表明:钢桥结构噪声波阵面为略显纺锤形的柱面波;纵、横梁和主桁为主要声源;纵、横梁和主桁的噪声峰值频段分别为1 000 Hz和630 Hz;随着至线路中心线的距离增加,近主桁辐射结构噪声衰减最快;近场噪声衰减速度比远场快。

In order to make out the noise characteristics of steel bridges of high-speed railways,the model for prediction of structure-borne noise of a composite steel truss bridge was established on the basis of the spatial vehicle-track-bridge coupling vibration theory and the statistical energy analysis （SEA）.The spatial distributing discipline of bridge-borne noise and the contribution of each component radiating noise were analyzed.The spatial hybrid beam-shell finite element model was used in analysis on spatial vehicle-track-bridge coupling interaction to obtain the vibration velocity time-histories of bridge deck and then by the FFT technique the velocity in the frequency domain was got and taken as the input of vibratory energy to SEA subsystems.The distributing and passing on results of system vibration energy were obtained by solving the statistical energy balancing equations.Finally the bridge structure-borne noise was derived according to the vibro-acoustic theory.Case study of a 64 m composite steel truss bridge shows as follows：The wave front of structure-borne noise is cylindrical wave slighty like spindles; the longitudinal beams,main trusses and crossbeams are the main sources of noise; the noise radiated by the longitudinal beams and crossbeams is dominated by the peak frequency band of 1000 Hz whereas 630Hz is the peak frequency band for noise from the main trusses; structure-borne noise radiated by the main truss close to running train has most attenuation along with increasing of the distance to the track center; the noise decay rate in the near field is higher than that in the far field.