利用层多重散射法分析了一种含圆柱形谐振散射体黏弹材料吸声层在钢背衬条件下的低频吸声特性.该吸声层由包覆软材料的圆柱空腔周期嵌入橡胶材料中构成,其中,散射体轴线与吸声层平行.结果表明,20mm厚吸声层在1000—3000Hz具有良好的吸声性能.通过综合分析单个散射体的吸收截面、单层周期散射体的声吸收、结构内部位移场以及耗散功率密度分布,揭示了该吸声层的低频吸声机理.
This paper investigates low-frequency acoustic absorption mechanism of a viscoelastic layer with resonant cylindrical scatterers. The viscoelastic layer is 20 mm-thick, and the cylindrical scatterer is a cylindrical cavity coated with a soft rubber layer, with axis in the lateral layer direction. The absorption properties of the viscoelastic layer under the steel-backing condition are studied using the layer-multiple scattering method. Results show excellent absorption performance in the frequency region of 1000—3000 Hz. The absorption mechanism is investigated by analyzing the absorption cross-section of a single scatterer and the multiple scattering of a periodic array of scatterers, together with the displacement field and power dissipation density. Effects of the resonant absorption of a single scatterer and the coupling resonance between the absorption layer and the steel-backing are revealed.