平面声波由空气经加肋板向水中传输的数值计算研究

Numerical analysis of sound transmission of an incident plane wave from air to water through stiffened plates

采用有限元法和边界元法计算研究了平面声波由空气经加肋板向水中的声传输。数值计算表明：板的刚度对声传输的影响只有在板的刚度较大时才是重要的，当板的刚度较小时，空气和水之间的声阻抗失配对声传输起支配作用；板厚或肋骨惯性矩的变化会引起结构传声损失曲线上隔声低谷位置的变化；增大板厚或肋骨惯性矩可增大结构的传声损失，特别是当激励频率低于结构基频时，可通过增大板厚或肋骨惯性矩来增大结构刚度进而明显增大结构的传声损失。

The sound transmission of an incident plane wave in the low-frequency range from air to water through stiffened plates mounted in an infinite baffle is investigated by using the finite element method and the boundary element method. The numerical results show that the influence of the stiffness of a plate on sound transmission is important if the plate's stiffness is large, and is insignificant if the plate's stiffness is small. In the latter case it is the big difference of characteristic acoustic impedance between air and water which dominates the sound transmission. The position of minimum values on the sound transmission loss curve varies with the changes made on plate thickness and the moment of inertia of stiffeners. An increase in the plate thickness and the moment of inertia of stiffeners increases the sound transmission loss, especially while the excitation frequency is below the fundamental natural frequency of the plate.