公路声屏障降噪性能数值模拟及结构优化

为提高公路声屏障的降噪性能,从声波绕射和反射两个角度考虑,通过声学有限元法(finite element method,FEM)分别探究声屏障顶端类型和表面扩散体间距、宽度以及高度对声屏障插入损失的影响,基于以上分析,提出一种适用于治理公路交通噪声的复合结构声屏障。结果表明,改变声屏障顶端和扩散体结构,对低频噪声影响较小;对于中、高频段,90°夹角的Y型声屏障降噪效果较好,在1 250～2 000 Hz频段内其插入损失较其他顶端类型可提升13 dB;当频率在1 000 Hz附近时,增加矩形扩散体的宽度、高度和间距可提高声屏障降噪效果;针对主要集中在800～1 250 Hz的公路交通噪声,设置复合结构声屏障可有效抑制声影区噪声辐射,附加扩散体后的复合声屏障与Y型声屏障相比,其插入损失最大可提高6 dB。

Numerical Simulation and Structure Optimization of Noise Reduction Performance of Highway Noise Barrier

In order to improve the noise reduction performance of highway noise barriers, this paper considers from two perspectives of sound wave bypassing and reflecting, and explores the effects of the top type of the noise barrier and the spacing, width, and height of the surface diffuser on the insertion loss of the noise barrier through the acoustic finite element method (FEM), respectively. Based on the above analysis, a composite structural noise barrier suitable for managing highway traffic noise is proposed. The study shows that changing the structure of the noise barrier tip and diffuser has less effect on the low-frequency noise. For the middle and high frequency bands, the 90° angle Y-type noise barrier has a better noise reduction effect, and its insertion loss can be improved by 13 dB compared with other tip types in the frequency band of 1 250~2 000 Hz. When the frequency is near 1 000 Hz, increasing the width, height and spacing of the rectangular diffuser can improve the noise reduction effect of the noise barrier. For highway traffic noise mainly concentrated in 800~1 250 Hz, setting the composite structure noise barrier can effectively suppress the noise radiation in the sound shadow area.The insertion loss of the composite noise barrier with additional diffusers can be increased by up to 6 dB compared with the Y-type noise barrier.