Bandgap characteristics of a novel self-similar chiral metamaterial

Abstract In this study, a self-similar chiral metamaterial (SSCM) is proposed. The proposed design replaces each junction of the fractal hexagonal framework with chiral units, effectively combining the broadband bandgap characteristics of fractal structures with the low-frequency bandgap advantage of chiral architectures, thus achieving an exceptionally wide low-frequency bandgap., while the vibration isolation performance is further enhanced through geometrical parameterization.Initially, a primary hexagonal unit cell is constructed, and a secondary hexagonal configuration is generated according to the fractal principle. Each connection point is then substituted with a chiral unit, and a pinned resonator is introduced inside the chiral element to form the final SSCM model. The proposed design is capable of generating a broad bandgap in the low-frequency region.By adjusting the structural morphology and geometric parameters of the metamaterial, the optimal configuration satisfying geometric integrity is obtained, and the variation of the bandgap with geometric parameters is analyzed. The finite element method (FEM) is employed to simulate the elastic wave propagation within the model, verifying the feasibility of the theoretical predictions. This metamaterial provide new insights and design strategies for the development of acoustic metamaterials in low-frequency noise and vibration control applications.