水下弹性微穿孔吸声结构吸声系数研究

利用模态叠加法建立了水介质微穿孔板的数学模型,基于声电类比法得到其等效电路模型。研究了弹性微穿孔板和弹性背腔对垂直入射吸声系数的影响。与空气介质中的微穿孔板不同,水下微穿孔板因结构阻抗不足,难以取得满意的吸声效果,为此提出了增强型微穿孔吸声结构,并在水介质阻抗管内对理论结果予以验证。结果表明,随着增强型弹性微穿孔板弯曲刚度的增大,其在[20,2000]Hz范围内的平均吸声系数得到提高,逐步趋近于刚性微穿孔板的结果,弹性背板使微穿孔吸声结构的吸声峰向低频移动,低频吸声效果得到提高。

Sound absorption characteristics of underwater flexible micro-perforated sound absorption structure

The mathematical model of micro-perforated sound absorption structure in water medium was established using mode superposition method,and the electro-acoustic analogy based equivalent circuit model was obtained.The influence of the vibration of Flexible Micro-Perforated Panel(FMPP) and Flexible Back Panel(FBP) on the sound absorption coefficient was studied.Because structural impedance of micro-perforated panel in water,different from that in air medium,was not sufficient to acquire the sound absorption effect,a strengthened micro-perforated sound absorption structure was proposed,and was verified in the water medium impedance tube.The results showed that,the average absorption coefficient of the strengthened micro-perforated panel in the range of [20,2000] Hz was improved and converged to that of rigid micro-perforated panel with the increase of bending stiffness.The absorption peak of Flexible Micro-Perforated Panel Cavity with Flexible Back Panel(FMPPCFBP) was shifted to the lower frequency,and sound absorption effect in low frequency was improved as well.