道路声屏障组合吸声结构设计与评估

声屏障在道路交通噪声污染防治中得到了广泛应用,但同时面临材料吸声性能有限、轻量化程度有待提升等问题。为了更好地提升道路声屏障的降噪效果,需要研究组合吸声结构的声学性能及其影响因素。建立了二维阻抗管有限元模型,与实验数据进行对比验证了其可靠性。基于有限元仿真构建了微穿孔板-双层多孔吸声材料-空腔组合吸声结构,研究了几何参数对组合结构的吸声性能的影响,并在实际道路场景中进行了仿真分析。结果表明,微穿孔板的孔径和厚度减小,组合结构在中高频段的吸声效果提升;穿孔率减小,组合结构在低频段的吸声性能提升,但是中高频吸声性能显著降低;多孔吸声材料厚度的增加能提升组合结构中高频吸声系数。在多孔吸声材料背后合理设置空腔并不会降低组合结构的声学性能。穿孔率3%,孔径0.4 mm,板厚1 mm的微穿孔板与3 cm聚酯纤维+3 cm三聚氰胺+2 cm空腔的组合吸声结构降噪效果较好,将其作为吸声型声屏障的材料。吸声型和隔声型声屏障插入损失的规律基本一致,采用组合吸声结构的吸声型声屏障较隔声型声屏障插入损失提升1-2 dB,能够较好地控制中低频交通噪声,具有实际工程价值。

Design and Evaluation of Composite Acoustic Structure for Road Sound Barriers

Sound barriers have been widely used in road traffic noise pollution prevention, however, they face problems such as limited sound absorption performance and lightweight grade of materials. In order to better improve the noise reduction effect of road sound barriers, it is necessary to study the acoustic performance of composite acoustic structures and their influencing factors. A two-dimensional finite element model of an impedance tube was established, and its reliability was verified by comparing it with experimental data. Based on the finite element simulation, a micro-perforated plate - double-layer porous acoustic material - cavity composite acoustic structure was constructed, and the influence of geometric parameters on the acoustic performance of the composite structure was studied and simulated in the road scenario. The results show that the aperture diameter and plate thickness of the micro-perforated plate decrease, the sound absorption effect of the composite structure in the medium-high frequency band is improved; the perforation rate decreases, the sound absorption performance of the composite structure in the low-frequency band is improved, but that in the medium-high frequency is significantly reduced; the increase in the thickness of the porous material improves the sound absorption coefficient in the medium-high frequency of the composite structure. The reasonable placement of cavities behind the porous material does not reduce the acoustic performance of the composite structure. The composite structure consists of a micro-perforated plate with a 3% perforation rate, 0.4 mm aperture diameter, and 1 mm plate thickness and 3 cm polyester fiber + 3 cm melamine + 2 cm cavity has a better noise reduction effect, and it was used as the material of the sound-absorbing acoustic barrier. The laws of insertion loss of sound-absorbing and sound-insulating sound barriers are basically the same. The insertion loss of the sound-absorbing sound barrier with composite structure was improved by 1-2 dB compared with that of the sound-insulating sound barrier. Therefore, the designed composite structure can effectively control traffic noise mainly at low and medium frequencies, which has practical engineering value.