静水压力下吸声覆盖层的声学性能分析

Effect of Hydrostatic Pressure on Acoustic Performance of Sound Absorption Coating

基于圆柱型空腔吸声覆盖层的二维解析理论,在只考虑黏弹性圆柱管中最低阶轴对称波的条件下,推导出圆柱管的平均阻抗,将变截面圆柱型空腔腔体单元近似为截面呈阶梯变化的多个圆柱管组合,用传输线组合描述整个腔体单元,以简化吸声覆盖层声学性能参数的计算方法;利用有限元软件分析了静压条件下吸声覆盖层的腔体单元变形,结合简化计算方法分析了静压对吸声覆盖层声学性能的影响.结果表明,静压作用于吸声覆盖层引起了腔体单元厚度减小和空腔半径缩小,使得吸声覆盖层的低频吸声性能变差,且吸声峰值向高频方向偏移.

Based on the two-dimensional analytic model of sound absorption coating which contains cylindrical cavities,the effective impedance of the viscoelastic cylindrical tube was derived by considering the propagating characteristics of the lowest-order axisymmetric wave.The unit cell of sound absorption coating which contains a deformed cylindrical cavity could be approximated as the combination of several uniform cylindrical cavities,and the transmission line theory was applied to describe the unit cell so that the simplified calculation method of the acoustic performance of sound absorption coating was obtained.The finite element software was used to calculate the deformation of the unit cell under the hydrostatic pressure,and the effect of the hydrostatic pressure on the acoustic performance of sound absorption coating was evalu-ated by using the simplified calculation method.The results show that the hydrostatic pressure causes the decrease of the unit cell thickness and the cavity size,both alternations lead to the bad low-frequency sound absorption performance,and the frequency of the peak absorption coefficient being shifted to the high frequency.