Design of vibration isolators by using the Bragg scattering and local resonance band gaps in a layered honeycomb meta-structure

In this study, a vibration isolator is designed using the Bragg scattering and local resonance band gaps in a layered honeycomb meta-structure. Various studies have been conducted on the noise and vibration problems of engineering structures by utilizing the band gaps in phononic crystal meta-materials. However, no study on the application of phononic crystal meta-materials to the design of vibration isolators has been published due to the large lattice constant and narrow band gap. To overcome the difficulties of realization in vibration isolators, a layered honeycomb meta-structure is proposed in this study. The proposed meta-structure consists of a layered square honeycomb structure and a local resonator placed inside the honeycomb core. A transfer matrix model based on the effective mass is developed to comprehend the mechanism of band gap formation. Furthermore, a strategy for designing an ultra-wide low-frequency coupled band gap is established analytically. Then, a four-layer honeycomb meta-structure is designed and fabricated based on the proposed design strategy. Experimental results demonstrate the successful realization of an ultra-wide coupled band gap with the introduction of the resonators with meticulously selected parameters. Finally, the designed meta-structure is applied to a vibration isolator, and the vibration isolation performance is verified experimentally. This work has broad engineering application prospects and is of high significance for promoting the implementation of elastic wave meta-materials in the engineering field.