Mode localiation phenomena of a multiple-wall structure and its application to active control

本研究的目的是提出一种基于模式局部化现象的抑制多壁腔体声辐射的方法，其中低频振动和/或声音被困在中间层中。首先，基于模式耦合方法，推导了多壁腔体的状态矩阵方程。其次，阐明了在柔性板之间能量传递中起重要作用的耦合项的存在，数值证明了通过最小化耦合项来实现局部控制。最后，针对多壁腔体的精确建模问题，通过引入传递矩阵法，提出了一种新的建模方法，该方法显式描述了声场的振动输入，并且在耦合面上质点速度不为零。

The objective of this study is to present a method for suppressing sound radiation from a multiple-walled cavity based on the mode localization phenomenon in which the low-frequency vibration and/or sound is trapped in the intermediate layer. First, based on the modal coupling method, a state matrix equation of a multi-walled cavity is derived. Next, the existence of the coupling term which plays an important role in energy transfer between flexible panels is clarified, numerically demonstrating that the localization control is achieved by minimizing the coupling term. Finally, in respect of the precise modeling of the multi-walled cavity, by introducing the transfer matrix approach, a novel modeling method is presented in which vibrational input to the acoustical field is explicitly described and particle velocity does not become zero at a coupling plane.