Inverse design of broadband acoustic metasurfaces for reflective wavefront modulation through the topology optimization method. (15th March 2023) - Li, Zhaoyu
Highlights: Topology-optimized design of reflective acoustic metasurfaces. Customized broadband acoustic metasurfaces with phase dispersion. Broadband metasurface mechanism analysis. Structural and methodological analysis of broadband metasurfaces. Abstract: The design of broadband acoustic metasurfaces is an important research challenge. Topology optimization with a genetic algorithm (TOGA) is used in this paper to design a set of reflection acoustic metasurfaces with discrete phase shift characteristics. This method allows the design of selective single-frequency and broadband metasurfaces. First, nine metasurface units are designed with a total phase gradient of 2 π at 3500 Hz. Simulations and experiments verify the anomalous reflection phenomenon of the metasurface in the reflected sound field and achieve wave focusing and self-bending functions by adjusting the position distribution of the units. Compared with single-frequency optimization studies, broadband acoustic metasurface units are designed with a linear phase dispersion in the range of 2000–5000 Hz, which achieves anomalous reflection with the same reflection angle and acoustic focusing phenomenon under broadband incident sound conditions. The ability of the algorithm to modulate the acoustic phase dispersion and the potential mechanism of generating different phase differences are further investigated. This method provides more accurate phase controllability for broadband acoustic metasurface optimization design and provides some ideas for the design of broadband structures in related fields.