Bragg scattering-driven anisotropic metabeam with multi-scale architecture for ultra-broadband vibration suppression at high structural stiffness

Abstract

Despite advancements in metamaterial beams, practical applications remain limited by narrow bandgaps, excessive mass, and stiffness compromises. This study presents a single-phase lightweight anisotropic metabeam leveraging Bragg scattering and hierarchical architecture optimization to achieve concurrent ultra-low frequency and ultra-broadband vibration suppression while preserving high stiffness. A novel non-locality homogenization method (NLHM) integrating variational asymptotic formulations and continuum mechanics is developed, enabling efficient prediction of static-dynamic properties with more than 90 % computational efficiency gain over traditional finite element method. Experimental characterization reveals triaxial stiffness anisotropy (x/z-direction modulus exceeding y-direction by 41.2 times and 56.8 times) and triphasic Poisson’s ratio behavior (–0.05 ≤ ν ≤ 0.42). Strategic exploitation of wave polarization in anisotropic media facilitates tri-modal vibration attenuation, achieving record relative bandwidths (ΔG) of 188.2 % (P-wave), 174.1 % (SH-wave), and 192.8 % (SV-wave). The metabeam demonstrates up to 59.8 dB peak attenuation and nearly 95 % wave confinement efficiency validated through laser vibrometry. This work establishes a paradigm for engineering multifunctional metamaterials through microstructure-mediated anisotropy, advancing the design of lightweight, high-stiffness vibration control systems.