Phononic crystals (PnCs) have seen increasing popularity due to band gap property for sound wave propagation. As a natural bridge, topology optimization has been applied to the design of PnCs. However, thus far most of the existent works on topological design of PnCs have been focused on single micro-scale topology optimization of a periodical unit cell. Moreover, practical manufacturing of those designed structures has been rarely involved. This paper presents a quasi two-scale topology optimization framework suitable for additive manufacturing (AM) implementation to design 2D phononic-like structures with respect to sound transmission coefficient (STC). A designate topology is employed and subjected to sizing optimization in the micro-scale design. The thin-walled square lattice structures made of single metal material are selected as the infills for the design domain to guarantee material connectivity in the optimized design in order to facilitate fabrication by AM. The practical effective mechanical property of the lattice structures with different volume densities obtained by experimental measurement is employed in the topology optimization. The proposed framework is applied to the design of 2D phononic-like structures with different macroscopic shapes for the desired band gap feature. Numerical examples show the desired band gap containing a prescribed excitation frequency can be realized through the proposed quasi two-scale topology optimization method. Moreover, the optimized designs are reconstructed into CAD files with the thin-walled lattice infills. The reconstruction makes fabrication of the optimized designs feasible by practical AM process.

由于声波传播的带隙特性，声子晶体（PnCs）越来越受欢迎。作为自然桥梁，拓扑优化已应用于PnC的设计。但是，到目前为止，有关PnC拓扑设计的大多数现有工作都集中在定期单位单元的单个微尺度拓扑优化上。此外，很少涉及那些设计结构的实际制造。本文提出了一种准两尺度拓扑优化框架，该框架适合于增材制造（AM）的实现，以针对声音传输系数（STC）设计2D类似于声子的结构。在微型设计中采用指定拓扑并对其进行尺寸优化。选择由单一金属材料制成的薄壁方格子结构作为设计领域的填充物，以确保优化设计中的材料连通性，从而有助于AM制造。通过实验测量获得的具有不同体积密度的晶格结构的实际有效机械性能被用于拓扑优化。所提出的框架被应用于具有期望的带隙特征的具有不同宏观形状的2D类似于声子的结构的设计。数值算例表明，通过提出的准两尺度拓扑优化方法可以实现包含规定激励频率的期望带隙。此外，使用薄壁晶格填充将优化的设计重建为CAD文件。