铝硅闭孔泡沫铝吸声性能研究

利用熔体转移发泡法制备了不同孔隙率(厚度为20mm;孔隙率为67.3%、77.7%、80.4%、88.1%)和不同厚度(孔隙率为79.6%;厚度为10、20、30mm)的铝硅闭孔泡沫铝,运用驻波管法对其吸声性能进行了测试,对其吸声机理进行了探讨,并研究了孔隙率和厚度对其吸声性能的影响.结果发现铝硅闭孔泡沫铝吸声主要是通过亥姆霍兹共振器结构和孔壁微孔以及裂缝等来实现的,实验进一步证实其吸声特性曲线符合理论分析.铝硅闭孔泡沫铝的孔隙率和厚度对其吸声性能影响显著:吸声系数随孔隙率增加而增加;低频阶段,吸声系数随厚度的增加而提高,高频阶段,吸声系数随厚度的增加而下降,但整体吸声性能受厚度影响较小,只出现了最高吸声系数向低频处迁移的现象.

Research on sound absorption property of Al-Si closed-cell aluminum foam

Al-Si closed-cell aluminum foams of different porosities(Thickness:20mm;Porosity: 67.3%,(77.7)%,80.4%,88.1%) and different thicknesses(Porosity: 79.9%;Thickness: 10mm,20mm,30mm) were prepared by the method of molten body transitional foaming process in this test;the sound absorption property was tested by utilizing standing waves tube,the sound absorption mechanism of which was studied,and the effect of porosity and thickness on its sound absorption property was also researched.It is found that the sound absorption property of Al-Si closed-cell aluminum foam mainly depends on the Helmholtz resonator,the microphone and cracks of material;the test further confirms that the curve of sound absorption characteristic of Al-Si closed-cell aluminum foam corresponds to theoretic analysis.The porosity and thickness affect markedly on the sound absorption property of Al-Si closed-cell aluminum foam: the sound absorption coefficient increases along with increasing porosity;increase of thickness can enhance the sound absorption coefficient at low frequency but reduce it at high frequency,but the contribution is not obvious for the whole sound absorption property,only appears the migratory phenomena of maximal sound absorption coefficient towards low frequency.