高速铁路桥梁结构噪声的全频段预测研究(Ⅱ):试验验证

Prediction of Structure-borne Noises of High-speed Railway Bridges in Whole Frequency Bands(Part Ⅱ):Field Test Verification

前1篇系列文章(《铁道学报》2013年第1期,作者:李小珍,等)基于车-线-桥空间耦合振动和稳态声辐射的边界元法、统计能量法理论,提出高速铁路桥梁结构噪声的全频段预测方法。本文以32m双线混凝土简支箱梁为例,将数值仿真分析与现场试验结果进行对比,验证理论模型的可靠性。分析结果表明:该箱梁的结构噪声主要出现在200Hz以下,沿垂直于线路方向的传播较远;噪声峰值出现在中心频率50Hz的频带,且在某些速度下具有明显的有调性;梁缝处的共鸣声较大,出现在中心频率315Hz的频带,沿垂直于线路方向的衰减较快。进行降噪处理时,可优先从噪声峰值频率入手,降低峰值频率处的结构噪声将更为有效。

In the companion paper, a prediction method of structure-borne noises of high-speed railway bridges in whole frequency bands was put forward on the basis of the the＇ories of the boundary element method（BEM）and statistical energy analysis（SEA） of train-track-bridge spatial coupling vibration and steady-state acoustic radia- tion. In this paper,a 32 m simply supported concrete box girder was selected for case study and field test results were compared with computed values to verify the reliability of the theoretical model. The analysis results indi- cate as follows： Structure-borne noises of the concrete box-girder appear mainly below 200 Hz and attenuate slowly in the direction perpendicular to the railway line;the maximum sound pressure level（SPL） lies in the the frequency band with the central frequency of 50 Hz, and it demonstrates the obvious tonal characteristic at some speeds;acoustic resonance at extension joints appears in the frequency band with the central freuqueney of 315 Hz and at remarkable degrees,how.ever its attenuation rate is fast in the direction perpendicular to the railway line. When measures are taken to conduct noise abatement, it is better to start from the frequency with the max- imum SPL,which would be more effective.