一种应用于电梯井的复合吸声结构及其吸声参数研究

Parameter study on a composite sound⁃absorbing structure lined on elevator shafts

为减弱电梯井噪声干扰,提出一种能应用于井内壁的复合吸声结构.基于Attenborough提出的“多孔材料表面声阻抗”理论和David and Colin提出的”穿孔板声阻抗”理论,探讨其吸声性能的参数优化方法.使用可与井壁一体化的阻尼石膏砂浆板为基材,复合岩棉板与水泥砂浆穿孔板组成井内壁吸声结构.基于理论分析、数值模拟与实验测量,通过分析该结构的岩棉板厚度、流阻、孔隙率等参数和穿孔板穿孔率、厚度、密度等参数对结构正入射吸声性能的影响,讨论了该吸声结构的参数优化方法.结果显示,岩棉板的孔隙率、流阻率和容重以及穿孔板的穿孔率、厚度对复合吸声结构性能起到关键性作用,增加穿孔板厚度、降低穿孔率、增加多孔材料的孔隙率可加强结构的低频吸声性能,反之则加强高频吸声性能;优化后的复合吸声结构,在600和1600 Hz的正入射吸声系数分别达到0.6和0.8.结果表明,提出的复合吸声结构在电梯井噪声控制中显然具有应用潜力.

In order to reduce the noise in elevator shafts,a composite sound-absorbing structure which can be applied to inner walls of elevator shafts is proposed.Based on the theory of"Acoustic impedance of porous material"proposed by K.Attenborough and the theory of"acoustic impedance of perforated plate"proposed by Bies,parameter optimization of sound absorption is discussed in the paper.The composite structure is composed of damping gypsum mortar board,composite rock wool board and cement mortar perforated board.Based on theoretical analysis,numerical simulation and experimental measurement,parameter optimization method of the sound absorption structure was discussed based on the influence of parameters,thickness,flow resistance and porosity of the rock wool board and perforation rate,thickness and density of the perforated board,on normal incidence sound absorption performance.Results show that porosity,flow resistance and bulk density of the rock wool board,and perforation rate and thickness of the perforated board play a key role in absorption performance.Increasing the thickness of the perforated board,reducing the perforation rate and increasing the porosity of the porous material can enhance absorption performance at low-frequencies.Normal incidence sound absorption coefficient of the optimized composite structure reaches 0.6 and 0.8 between 600 and 1600 Hz,respectively.The proposed composite sound-absorbing structure has application potential in elevator shaft noise control.