声子晶体型高速公路声屏障的降噪性能

利用高速公路改扩建工程产生的大量废旧护栏立柱，针对高速公路轮胎-路面主要噪声，建立三种二维气-固型声子晶体声屏障.利用Comsol Multiphysics计算相应的能带结构，并探究带隙的影响因素.结果表明3种形式均可以产生相应的带隙；散射体壁厚大小对于带隙宽度影响很小，但采用空心散射体可以在低频产生一条完全禁带；对散射体进行开口处理可以有效增加低频带隙宽度；当晶格填充率增大至0.5后，随着填充率增大，从高频到低频依次产生完全禁带，且带隙总宽度增大；通过仿真模拟与室内实验相结合的方式验证了声屏障的降噪特性，声屏障在带隙范围内具有良好的降噪性能，相较直立同规格复合板声屏障，低频降噪效果提升1~16dB，高频降噪效果提升1~2dB，但在1600Hz后，声子晶体声屏障降噪效果不及复合板声屏障，降噪效果受周期数影响较大.声子晶体声屏障可实现新型降噪理念与绿色环保的有机结合.

Noise reduction performance of highway sonic crystals noise barrier

Three types of air-solid sonic crystals noise barriers were established for the tyre-road noise which is the main noise of highway by using recycled columns of the fence. Comsol Multiphysics was used to calculate the corresponding band structure and explore the influencing factors of band gaps. The results showed that the three forms can generate corresponding band gaps; the wall thickness had little effect on the band gap width, but the hollow scatterers could generate a complete band gap at low frequencies; opening treatment of the scatterers could effectively increase the low band gap width; after the lattice filling rate reached 0.5, complete band gaps were generated in order from high to low frequencies, and as the filling rate increased, the band gap overall width increased. The noise reduction characteristics of the barrier were verified through a combination of simulation and indoor experiments, the sonic crystals noise barrier had good noise reduction performance in the band gap range, compared with the aluminum alloy composite board noise barrier with the same specifications. The low-frequency noise reduction effect was increased by 1~16dB, and the high-frequency noise reduction effect was increased by 1~2dB; however, after 1600Hz, the noise reduction effect of the sonic crystals noise barrier did not outperform the composite board barrier, and the noise reduction effect was greatly affected by the number of cycles. The sonic crystal noise barrier is a promising combination of new noise reduction concepts and green environmental protection.