嵌入粘弹性包覆层的吸声覆盖层低频性能研究

在单层牯弹性圆柱管吸声覆盖层的基础上,发展了嵌入低剪切波波速包覆层即双层粘弹性圆柱管的吸声结构的理论模型.推导了轴对称波特征方程的低频近似解,并根据牛顿迭代法进一步计算精确解,为吸声覆盖层的低频性能快速预报提供基础.数值分析表明包覆层嵌入比例的增加、或者包覆材料剪切波速的减小能有效地改善低频吸声性能.

Study on Low-frequency Characteristic of Sound Absorption Layer by Embedding viscoelastic Coated Material

Based on the single-layer viscoelastic cylindrical tube model for sound absorption layer,the double-layer tube model by embedding viscoelastic coated material with low speed of shear wave was developed.The low-frequency approximate solution to the characteristic equation of ax-isymmetric wave is derived,and the exact solution is obtained subsequently using Newton iteration method,then it is feasible to estimate rapidly the sound absorption performance at low frequencies. Numerical results show that with the proportion of coated material increasing or with the shear wave speed of coated material decreasing,the sound absorption performance at low frequencies is im-proved.