折叠背腔微穿孔结构的宽频吸声特性研究

Broadband Sound Absorption Characteristics of the Micro-perforated Structure with a Folded Back Cavity

为拓宽吸声带宽,提高低频吸声效果,提出新型折叠背腔微穿孔板吸声结构。建立单个折叠背腔微穿孔吸声单元的理论模型,通过传递矩阵法求解其吸声系数,通过有限元仿真验证理论计算结果。在此基础上,分析由不同背腔深度单元组成的折叠背腔微穿孔板吸声结构的垂直入射吸声特性。随着组合单元数目的增加,吸声带宽得到进一步拓展。结果表明,整体厚度仅为30.3 mm的10单元组合折叠背腔微穿孔板吸声结构在450 Hz~1 600 Hz内的吸声系数大于0.6,在1 200 Hz~1 550 Hz范围内的吸声系数大于0.8。

To broaden the sound absorption bandwidth and improve the low frequency sound absorption effect, a new type micro-perforated panel sound absorption structure with a folded back cavity is proposed. Theoretical model of the structure is established, and the sound absorption coefficient is solved with transfer matrix method, and the correctness of the results are verified by finite element simulation. On this basis, the micro-perforated sound absorption units are combined with the folded back cavity of different depth, and their vertical incident sound absorption performances are analyzed. The results show that with the increase of the number of the combined units, the sound absorption bandwidth is broadened. The sound absorption coefficient of the sound absorption structure with 10 units of the combined folded back cavity micro-perforated panels with 30.3 mm thickness is greater than 0.6 in the frequency range of 450 Hz-1 600 Hz and greater than 0.8 in the frequency range of 1 200 Hz-1 550 Hz.