多层结构连续铜纤维材料吸声性能研究

Exploring Sound Absorption Performance of Multi-Layer Copper Fiber Sturcture

采用直径分别为0．22mm、0．30mm和0．62mm的铜纤维，制备出铜纤维多孔材料单层板并组合成双层和三层吸声结构；研究后空腔深度：中空腔深度、后空腔和中空腔深度同时作用以及三层结构等因素对吸声性能的影响；研究结果表明，随着后空腔深度的增加有利于中低频吸声性能的改善，在第一吸收峰与第二吸收峰之间明显出现吸收的谷，降低了1000～3000Hz吸声性能；随着中空腔深度的增加，曲线向低频移动，共振吸声系数下降，第一吸收峰与第二吸收峰之间的吸收谷加深，谷的宽度减小，对1000～3000Hz范围吸声性能的影响减小，吸声系数基本都大于0．5；当中空腔和后空腔同时增加时，可有效抑制吸收谷深度的加深，中低频吸声性能提高；三层多孔材料与双层多孔材料构成的双空腔结构，前者的吸声系数曲线完全包罗了后者，前者的吸声性能优于后者。

We use the copper fibers of diameters of 0. 22 mm, 0. 3 mm and 0. 62 mm to prepare a single-layered copper fibrous porous plate and incorporate it into double and three layered sound absorption structure. We also study the effects of the depths of rear cavity and central cavity and of the depth of both types of cavity in action at the same time on the sound absorption performance of the sound absorption structure. The study results and their a- nalysis show preliminarily that： （ 1 ） the increase of the depth of rear cavity helps improve the medium and low fre- quency sound absorption performance, yet there is an apparent valley of sound absorption between the first and sec- ond absorption peaks, thus reducing the sound absorption performance in the frequency range between 1 000 Hz and 3 000 Hz ; （2） the increase of the depth of central cavity moves the absorption curve to the low frequency and reduces the resonance absorption coefficient, with the absorption valley between the first and second absorption peaks being deeper and its width being smaller, thus having less effect on the sound absorption performance of the sound absorption structure between 1 000 Hz and 3 000 Hz; in both cases, the sound absorption coefficient is more than 0. 5 ; （3） the increase of the depth of both types of cavity can effectively suppress the depth of the absorption valley and enhance the sound absorption performance in the medium and low frequencies. The sound absorption co- efficient curve of the three-layered porous copper fibrous structure with double cavities completely encompass that of the double-layered porous copper fibrous structure, while the sound absorption performance of the former is superior to that of the latter.