Syndiotactic chiral metamaterial absorber for low-frequency broadband vibration reduction

Abstract

The compression-twist coupling effect of chiral metamaterials provides new insights into the development of broadband absorbers. This study proposes a novel syndiotactic chiral metamaterial absorber (SCMA), which combines a syndiotactic chiral metamaterial frame with twisted beams. The proposed SCMA leverages the coupled vibration and inertial amplification effects, which allows to suppress the low-frequency broadband vibration. By adjusting the twist angles of the beams, the vibration suppression band and the maximum amplitude can be optimized. A three-dimensional (3D) elastic wave model and a discrete oscillator model are then developed to study the modal characteristics and damping mechanism of the SCMA. Afterwards, the impacts of the ligament angles and the slenderness ratio of the chiral metamaterial frame on the vibration suppression bandwidth are systematically evaluated. The obtained results show that, compared with conventional linear vibration absorbers (LVA), the SCMA reduces the amplitude by 24.8 % and expands the vibration suppression bandwidth by a factor of 10. The experimental results are consistent with the predictions of the theoretical models. The high damping performance and significantly broadened attenuation bandwidth of the proposed SCMA provide a high potential for enhancing the structural integrity of machinery.