舱壁厚度受限的低频宽带吸声结构研究

Study of Low-Frequency Broadband Sound Absorption Structures with Restricted Bulkhead Thickness

由于现代舰船的舱壁厚度过大且低频噪声控制能力有限,为实现舱壁结构轻质、吸声等多功能的高度集成,设计一种基于内插管型Helmholtz谐振腔多胞元组合排布的低频宽带吸声结构。采用Comsol软件建立压力-热黏性声学有限元模型,分析对比各排布构型结构的低频吸声性能,获得500 Hz~900 Hz内平均吸声系数大于0.9的宽带吸声结构。结果表明:较高面积占比的构型能在低频段获得更高的吸声峰值和吸声带宽,其结构更易实现阻抗匹配,提升结构的吸声性能;等截面积的类矩形Helmholtz谐振腔胞元在进行环形排布组合后,过薄壁厚会引起相邻胞元之间的不良耦合,降低结构的吸声性能。

Since the bulkhead thickness of modern ships is too large and the ability to control low-frequency noise is limited,a low-frequency broadband acoustic structure based on a multi-cell arrangement of Helmholtz resonator is designed to achieve a high degree of integration of light weight,sound absorption and other multi-functional bulkhead structures.The pressure-thermal viscous acoustic finite element model is established using Comsol software to analyze and compare the low-frequency sound absorption performance of each arrangement configuration structure,and a broadband sound absorption structure with an average absorption coefficient greater than 0.9 in 500 Hz~900 Hz is obtained.The results show that the configuration with higher area ratio can obtain higher peak and bandwidth in the low frequency band,and its structure is easier to achieve impedance matching and improve the structural absorption performance;The combination of rectangular-like Helmholtz cells with equivalent cross-sectional area in a circular arrangement causes poor coupling between adjacent cells due to the thin wall thickness,which can reduce the structural absorption performance.