含有空气背衬层的分层多孔材料的吸声性能研究

摘要

根据声波在介质中的传播规律，计算了声波垂直入射到含有空气背衬层的分层多孔材料吸声结构的吸声系数。以含有空气背衬层的双层泡沫铝结构为例，研究了各层泡沫铝的设计参数和空气背衬层厚度变化对吸声结构吸声系数的影响规律。研究表明：随着各层孔隙率增加、或厚度增加、或流阻率增加，双层泡沫铝空气背衬层吸声结构的吸声系数逐渐增大；在低频段增加空气背衬层厚度，吸声系数增大，且最高吸声系数表现出向低频迁移的趋势；在中频段，当增加各层孔隙率或流阻率时，没有空气背衬层的双层泡沫铝吸声结构则呈现出更好的吸声性能。合理调整各层材料的设计参数，可在较宽频段上达到满意的吸声效果。%Based on the transmission equation of acoustic wave in a layered media ,the absorption coefficient of the multilayer porous material backed with an air gap is calculated .Taking a double-layer Aluminum foam backed with an air gap for an ex-ample ,the effect of acoustic parameters of each layer and thickness of air gap on the absorption coefficient is analyzed .The re-sults show that the absorption coefficient of the sound absorption structure with an air gap gradually increases with the increase of porosity ,thickness ,and flow resistivity of each porous material respectively .At low frequency ,increasing the thickness of air gap will lead to the increase of the absorption coefficient ,and the maximum absorption coefficient shifts towards lower fre-quencies .At intermediate frequency ,the sound absorption structure without the air gap shows a better sound absorption prop-erty when the porosity or flow resistivity are increased .Therefore ,the sound absorption level can be achieved in a wider fre-quency range through the adjustment of material parameters of each layer .