声子晶体型高速公路声屏障的降噪性能

Utilizing a large number of waste guardrail posts generated from expressway reconstruction and expansion projects, three types of two-dimensional gas-solid photonic crystal sound barriers are established for the main noise of expressway tires and pavements. The corresponding energy band structures are calculated using Comsol Multiphysics, and the influencing factors of the band gaps are explored. The results show that all three forms can produce corresponding band gaps; the thickness of the scatterer wall has little influence on the width of the band gap, but using a hollow scatterer can produce a complete band gap at a low frequency; opening the scatterer can effectively increase the width of the low-frequency band gap; when the lattice filling rate increases to 0.5, as the filling rate increases, complete band gaps are generated from high to low frequencies in turn, and the total width of the band gaps increases; the noise reduction characteristics of the sound barrier are verified through a combination of simulation and indoor experiments. The sound barrier has good noise reduction performance within the band gap range. Compared with the vertical composite board sound barrier of the same specification, the low-frequency noise reduction effect is improved by 1 - 16 dB, and the high-frequency noise reduction effect is improved by 1 - 2 dB. However, after 1600 Hz, the noise reduction effect of the photonic crystal sound barrier is not as good as that of the composite board sound barrier, and the noise reduction effect is greatly affected by the number of periods. The photonic crystal sound barrier can achieve an organic combination of a new noise reduction concept and green environmental protection.

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.