Bandgap optimization and inverse design of labyrinth metamaterials for sound insulation

Acoustic metamaterials are novel functional materials that can be artificially designed and have unusual properties like the bandgap, holding immense potential for applications in noise control. However, a low -frequency and broadband bandgap investigation and the inverse design of metamaterials at desired bandgaps remain challenging. In this study, taking the highway noise issues as an example, a kind of simplified labyrinth metamaterials (SLMM) is designed to address this problem. A narrow bandgap opens at low frequency due to the effect of artificial Mie resonances. Then, the position and bandwidth of the first bandgap were optimized using the multi -objective genetic algorithm (GA). The lower limit of the initial bandgap can reach 317 Hz, with the potential for a bandwidth extension up to 550 Hz. Furthermore, GA -combined methods with the absolute value method or penalty function method are proposed. The results indicate that this method has a fast calculation speed and small errors, with an absolute error of only 0.045 for the absolute value method. Then bandgap splicing is introduced to get wider bandgap. The experimental results indicate that the combined structure can achieve wideband attenuation of sound waves, about 31 dB acoustic energy attention is obtained from 400 Hz to 2500 Hz, consistent with the expected outcomes from simulations. The proposed method has a clear and easy -to -understand principle, robust performance, and can be extended based on specific requirements by adjusting the objective function, which shows the capability of both bandgap optimization and inverse design methodology for metamaterials.