Three-dimensional chiral meta-plate lattice structures for broad band vibration suppression and sound absorption

Abstract

Phononic crystals (PCs) and acoustic metamaterials (AMs) have been studied due to their unique performance in generating elastic wave bandgaps. However, for vibration isolation structures with load bearing requirements, the conflict between stiffness and vibration control of the periodic structures is still a major concern. This paper presents a new type of three dimensional (3D) single-phase meta-plate lattice (MPL) structure consisting of chiral microstructures. The chirality is constructed by grooving the unit-cell surface of the plate-lattice structures with high bearing capacity. When the elastic wave propagates through the lattice structure, the energy is absorbed by the multiple vibration modes of the chiral surface, thus achieving the effect of broadband vibration reduction. In order to illustrate the isolation effect and the cause of bandgap formation, the propagation characteristics of elastic waves in a meta-plate beam are studied numerically and the isolation effect of the proposed lattice structures are validated by the vibration transmission tests. The sound absorption experiment is also carried out to evaluate the sound absorption performance of the new structure. This work offers an innovative method to develop new multi-functional lattice structures with both load bearing, vibration attenuation and sound reduction requirements. Vibration isolation effectiveness of MPL structure: (a) Experimental set-up and printed MPL structure. (b) Transmission spectrums obtained by simulation and experiment. (c) Transient responses at the input and output ends of the beam under 1991 Hz.