闭孔泡沫铝吸声性能的影响因素

Influence factors of sound absorption properties of closed-cell aluminum foam

利用熔体转移发泡法制备闭孔泡沫铝,从孔径大小、打孔率、背后空腔以及背后贴膜方面对其吸声性能进行研究。结果表明:孔径大的闭孔泡沫铝吸声系数要远好于孔径小的闭孔泡沫铝的吸声系数;打孔后闭孔泡沫铝吸声系数有了明显的提高,当分别打孔0.5%、1%和2%后,闭孔泡沫铝最高吸声系数从0.42分别增加到了0.53、0.75和0.96;打孔闭孔泡沫铝背后加空腔吸声曲线都表现出明显的亥姆霍兹共振器吸声特性,且随空腔厚度的不断增加,低频吸声系数逐渐增加,高频吸声系数逐渐降低,最高吸声系数向低频迁移;背后贴膜闭孔泡沫铝吸声特性曲线出现峰值吸声特征消失的现象,表现出吸声系数随频率增加而增加的特性。

Closed-cell aluminum foam was prepared by the method of molten body transitional foaming process, and the sound absorption properties were studied from the aspects of cell diameter, perforation rate, cavity thickness and aluminum foil attached behind. The results show that at the same porosity, the sound absorption coefficient of closed-cell aluminum foam with larger cell diameter is larger than that with smaller cell diameter; the sound absorption coefficient of closed-cell aluminum foam increases obviously after being perforated, when the perforation ratios are 0.5%, 1% and 2%, the highest sound absorption coefficient can reach 0.53, 0.75 and 0.96 from 0.46, respectively; the sound absorption curves of closed-cell aluminum foams after being perforated show obvious sound absorption characteristic of Helmholtz resonator; with increasing the cavity thickness, the sound absorption coefficient increases under low-frequency region, and decreases under high-frequency region; the highest sound absorption coefficient increases slightly, but shows the trend of traveling to low-frequency region; the peak sound absorption characteristics disappear when the closed-cell aluminum foams are attached with aluminum foils, and the sound absorption coefficient shows increasing characteristic with in creasing frequency.