【作者】 刘玲；

【导师】 蔡俊；

【作者基本信息】 上海交通大学 ， 环境工程（专业学位）， 2013， 硕士

【摘要】 声屏障作为防治道路交通噪声污染的有效途径，在道路交通噪声污染防治中得到较大的应用。建造道路声屏障相对于车辆本身的噪声治理虽然被动，但仍然是改善道路沿线居住和办公环境的有效措施。交通噪声主要通过透射、反射和绕射到达声屏障后方的受声点，而绕射成为降低声屏障降噪性能的主要因素。因此声屏障顶部结构的设计成为研究的热点。国内外研究表明，大多数声屏障对中高频噪声作用显著，对中低频声音效果并不明显，而交通噪声主要集中在中低频。为了增加声屏障对中低频噪声的降噪作用，论文将二次余数扩散体应用于声屏障顶部，并对该结构展开了一系列的优化研究。本文针对穿孔板/微穿孔板二次余数扩散体复合结构在声屏障顶部结构上的应用，以治理道路交通噪声问题进行了一系列的研究。其中包括数值模拟、二次余数扩散体缩尺模型阻抗管实验优化研究以及对顶端结构为二次余数扩散体的声屏障结构进行插入损失的优化研究。数值模拟采用大型声学测试分析软件SYSNOISE对直立型及顶端为二次余数扩散体结构的声屏障进行数值模拟，确定声屏障顶端应用二次余数扩散体结构后降噪性能得到很好的改善，其插入损失比直立型声屏障高3-7dB。二次余数扩散体缩尺模型阻抗管实验抗性优化研究表明，二次余数扩散体结构经过与穿孔板/微穿孔板复合之后，同时获得了两种结构的优点，吸收峰明显改善，从0.2提高到0.6以上；阻抗率与吸声系数具有一定的相关吻合性，其声抗幅值基本和吸声系数峰值所在的频带范围重合。顶部为二次余数扩散体结构的声屏障半消声室实验优化研究主要将二次余数扩散体与抗性结构进行复合，二次余数扩散体顶部声屏障的降噪性能起到很大的优化作用，尤其是当二次余数扩散体结构与板厚为0.8mm，穿孔率为2%的微穿孔板复合时，优化作用相当明显，比单一二次余数扩散体结构高5dB。针对目前传统的声屏障在中低频降噪效果非常差的现状，这种新型的二次余数扩散体型声屏障在中低频则有非常好的降噪效果，非常适合应用于交通噪声的治理，有很广阔的应用前景，这也为以后城市道路声屏障的设计提供重要的理论基础和参考依据。更多还原

【Abstract】 As an efficient method to prevent traffic noise, noise barriers havebeen commonly used. Though it is relatively passive to construct noisebarriers to control traffic noise, they are very effective to improve theliving environment and the office environment which along the roads.Traffic noise reaches to the point behind the sound barrier mainlythrough transmission, reflection and diffraction. Diffraction is one of themain factors which reduce the insertion loss of the noise barrier. Andbased on this, the research of the top structure of noise barriers become theresearch hot spot. The domestic and international research shows that mostnoise barriers can reduce the high frequency noise significantly, but theeffect to the low frequency is not obvious. The traffic noise mainlyconcentrated in the low frequency, so it is necessary to reduce the lowfrequency noise caused it.According to characteristic of traffic noise which focuses on middleand lower frequency, a noise barrier with Quadratic Residue Diffuser wasapplied. We use SYSNOISE which is a kind of acoustic simulationsoftware to calculate the noise barrier model which QRD was applied on.According to the test in the impedance tube and the semi-anechoic room,we also analysis the absorption coefficient of QRD and the noise reductionperformance of noise barrier with QRD on itSYSNOISE simulation software was used to calculate the insertionloss of the erect noise barrier and the noise barrier with QRD top. Theexperimental results show that while the QRD was used as a top on the noise barrier, the insertion loss was3-7dB higher than the erect one.The experimental results in the impedance tube shows that whenQRD was composited with perforated plate and microperforated plate, thecomposite structure presented the performance of both the QRD and theperforated plate and microperforated plate. Both the absorption peak andthe half-peak width were highly improved. The absorption peak wasimproved to0.6from0.2. And also, we can get that the specific acousticimpedance was in accordance with the acoustical absorption coefficient.The frequency bandwidth of the acoustic resistance amplitude was in theabsorption coefficient half peak width.While QRD was combined with the resistance structure such asperforated plate and microperforated plate, the noise reductionperformance of the noise barrier with the composite structure was highlyoptimized. The composite structure with the microperforated plate whichthe thickness is0.8mm and the perforated percentage is2%was the beststructure. And the insertion loss of this composite structure is5dB higherthan the noise barrier just with the QRD.The noise barrier with QRD top has a high noise reduction thantraditional noise barrier, so it has a wide prospect. Meanwhile, the QRDnoise barrier will also provide the theory and practice reference toresearchers in the field of barrier design.更多还原