高声压级时多孔金属板的吸声特性研究

针对高声压级下有限厚度多孔金属板在线性阻抗背衬条件下(背衬表面声压与声质点速度为线性关系)的吸声问题,提出了一个描述不同声压级下材料层法向吸声性能的一维模型,并给出求解材料层内部声质点速度的线化与差分方法,以预测多孔金属板在高声压级下的非线性吸声特性。在阻抗管中对两块多孔金属板进行了声学测试,得到了材料层法向表面阻抗和吸声系数随入射声压级变化的实验结果。研究表明:实验与理论预测符合良好,验证了模型与数值方法的正确性。本文所提原理和方法,可用于一般硬质多孔材料。

Investigation on the sound absorption characteristics of porous metal plates at high sound pressure levels

A one-dimensional model is proposed for sound absorption of a porous metal plate with finite thickness at high sound pressure levels(SPLs),where the sound pressure is linear with the particle velocity at the back of the plate.In order to predict nonlinear acoustic performance,the particle velocity inside the porous plate is solved by a linearization and finite difference method.Acoustic measurement for two porous metal plates was performed in an impedance tube;the normal surface impedance and sound absorption coefficient at different SPLs were obtained.Good agreement between the experimental and theoretical results validates this model.The method developed here can be also applied to other rigid porous materials.