Using the active feedback control system on the elastic wave metamaterial, this research concentrates on the sound transmission with the dynamic effective model. The metamaterial is subjected to an incident pressure and immersed in the external mean flow. The elastic wave metamaterial consists of double plates and the upper and lower four-link mechanisms are attached inside. The vertical resonator is attached by the active feedback control system and connected with two four-link mechanisms. Based on the dynamic equivalent method, the metamaterial is equivalent as a single-layer plate by the dynamic effective parameter. With the coupling between the fluid and structure, the expression of the sound transmission loss (STL) is derived. This research shows the influence of effective mass density on sound transmission properties, and the STL in both modes can be tuned by the acceleration and displacement feedback constants. In addition, the dynamic response and the STL are also changed obviously by different values of structural damping, incident angle (i.e., the elevation and azimuth angles) and Mach number of the external fluid with the mean flow property. The results for sound transmission by two methods are compared, i.e., the virtual work principle for double plates and the dynamic equivalent method corresponding to a single one. This paper is expected to be helpful for understanding the sound transmission properties of both pure single- and double-plate models.

本研究使用弹性波超材料上的主动反馈控制系统，着重研究具有动态有效模型的声音传递。超材料受到入射压力，并浸入外部平均流中。弹性波超材料由双板组成，上下四连杆机构安装在内部。垂直谐振器由主动反馈控制系统连接，并与两个四连杆机构连接。基于动态等效方法，通过动态有效参数将超材料等效为单层板。通过流体与结构之间的耦合，可以得出声传输损耗（STL）的表达式。这项研究表明有效质量密度对声音传输特性的影响，两种模式下的STL均可通过加速度和位移反馈常数进行调整。此外，具有平均流量特性的外部流体的结构阻尼，入射角（即仰角和方位角）和马赫数的不同值，也会使动力响应和STL发生明显变化。比较了两种方法传声的结果，即双板的虚拟工作原理和对应于单个板的动态等效方法。希望本文对理解纯单板和双板模型的声音传输特性有所帮助。带有平均流量特性的外部流体的马赫数）（仰角和方位角）和马赫数。比较了两种方法传声的结果，即双板的虚拟工作原理和对应于单个板的动态等效方法。希望本文对理解纯单板和双板模型的声音传输特性有所帮助。带有平均流量特性的外部流体的马赫数）（仰角和方位角）和马赫数。比较了两种方法传声的结果，即双板的虚拟工作原理和对应于单个板的动态等效方法。希望本文对理解纯单板和双板模型的声音传输特性有所帮助。