Locally multi-resonant meta-shells for broadband vibration suppression.

• A configuration of multi-resonant meta-shell is proposed. • Generalized theoretical model of meta-shell is established. • Equal ratio gradient is used for lightweight and broadband design. • Broadband vibration suppression is experimentally verified. This paper presents the design of a meta-shell with spring-mass resonators periodically attached onto a cylindrical shell to achieve low-frequency, broadband vibration suppression. The dispersion relations of the meta-shell are calculated using Hamilton's principle in conjunction with the plane wave expansion (PWE) method, which is verified by the finite element method (FEM). The bandgaps in different wave propagation directions are observed which is induced by the dynamic negative effective mass density. The effects of different meta-shell parameters on bandgap behavior are investigated, from which the fine-tuning of bandgaps can be achieved. The vibration propagation in finite meta-shells is then studied using FEM and the attenuation of vibration is demonstrated in the frequency range of the bandgap. To further broaden the bandgap frequency range, we propose a gradient configuration of a multi-resonant meta-shell in which the resonant frequencies of multiple sets of resonators comply with equal ratio distribution. Compared with the single-resonator meta-shell, it is shown that a 170.7 % expansion in bandwidth can be achieved while the total mass of the resonators is reduced by 41.5 %. Finally, the vibration suppression performance of the multi-resonant meta-shell is experimentally verified, demonstrating the broadband vibration attenuation in corresponding bandgap frequency ranges. This work shows promising application potentials for the multi-resonant meta-shells in vibration control engineering. [Display omitted] [ABSTRACT FROM AUTHOR]