Broadband low-frequency vibration attenuation in 3D printed composite meta-lattice sandwich structures

摘要

Achieving superior properties of vibration suppression at low-frequency range, yet with high load-bearing capabilities in lightweight structural designs is still a challenge. In this work, we propose a strategy to realize broadband low-frequency vibration bandgaps by combining the design concepts of locally resonant metamaterials and lightweight lattice-truss-core sandwich structures. Two kinds of meta-lattice sandwich panels consisting of single/double-layer pyramidal truss-cores are designed, and the 3D printing technique of selective laser sintering (SLS) is applied to fabricate the dissipative composite meta-structures. The vibration suppression performance and bandgap generation mechanisms are theoretically, numerically, and experimentally investigated. Remarkable vibration suppression within broadband low-frequency bandgaps, stemming from the coupling between the designed secondary structures and host panels, are numerically and experimentally verified in both time and frequency domains. Equivalent mass-spring models are developed to theoretically predict the vibration attenuation ranges. Bandgap merging effects induced by the damping of the 3D printed metastructures are further investigated, and remarkably enlarged attenuation bands are experimentally captured. The metamaterial-based lattice sandwich structures pave feasible ways for designing vibration shielding systems with both high functional and mechanical performance.