Open acoustic barriers exhibit excellent sound transmission reduction property at a certain frequency/frequencies which highly depends on the configuration of its unit cell. Design of unit cell configuration for minimum sound transmission at predefined objective frequency remains an open question. This paper aims at providing an automatic design method for open acoustic barriers with multi-material unit cell. Firstly, a wave finite element method is developed to calculate the sound transmission through an infinite array of periodic scatterers. As the unit cell contains infinite fluid domain, the application of Floquet-Bloch theorem to the boundaries of perfectly match layers (PML) is necessary and has been resolved in this paper. This wave finite element method with the implementation of PML is validated by comparing to analytical solution of sound transmission through an array of steel cylinders. Then a genetic algorithm is employed to optimize the sound transmission loss with respect to material distribution of a bi-material unit cell. Finally, the effectiveness of this inverse design is demonstrated by examples with different predefined frequencies. Corresponding unit cell typologies are obtained and the dips of sound power transmission coefficient curve are successfully tuned to objective frequencies.

开放式声屏障在一定频率/频率下表现出出色的声音传输降低性能，这在很大程度上取决于其单位单元的配置。在预定义的目标频率下实现最小声音传输的单位单元配置设计仍然是一个未解决的问题。本文旨在提供一种具有多材料单元格的开放式声屏障的自动设计方法。首先，发展了一种波有限元方法来计算通过无限个周期性散射体阵列的声音传输。由于晶胞包含无限的流体域，因此有必要将Floquet-Bloch定理应用于完全匹配层（PML）的边界，并且已在本文中对其进行了解决。通过与通过钢瓶阵列传播声音的解析解决方案进行比较，验证了采用PML的这种波浪有限元方法。然后，采用遗传算法相对于双材料单位单元的材料分布来优化声传输损耗。最后，通过具有不同预定义频率的示例证明了这种逆向设计的有效性。获得了相应的单元格类型，并将声功率传输系数曲线的谷值成功地调谐到目标频率。通过具有不同预定义频率的示例证明了这种逆向设计的有效性。获得了相应的单元格类型，并将声功率传输系数曲线的谷值成功地调谐到目标频率。通过具有不同预定义频率的示例证明了这种逆向设计的有效性。获得了相应的单元格类型，并将声功率传输系数曲线的谷值成功地调谐到目标频率。