Harnessing bulging or sloshing modes to design locally resonant liquid-solid metamaterials

Abstract

This paper proposes harnessing bulging or sloshing modes to design locally resonant liquid-solid metamaterials that can be applied to vibration isolation engineering. The longitudinal dynamic effective mass of the proposed bulging or sloshing cell is analyzed through the assumed mode method and the finite element simulation. The meta-structure consisting of a sequence of unit cells is studied as well. In a certain frequency regime, the proposed bulging metamaterial can block the propagation of elastic longitudinal waves and convert the energy of the host structure to the bending energy of localized covering plates. This longitudinal-to-transverse conversion is triggered by the coupled vibration of the internal liquid and the covering plate. This feature can be applied to energy harvesting. In terms of the sloshing metamaterial, it can attenuate elastic longitudinal waves in an extremely low-frequency range. The local resonance frequency and the bandwidth of the sloshing metamaterial can be tuned by altering the liquid height. Additionally, we exhibit equivalent pendulum-like models to understand the vibration behavior of the bulging and sloshing cells. The proposed liquid-solid metamaterials can provide new approaches for vibration isolation and mechanical energy harvesting. The concept presented here may also give inspirations to designing other multi-physics metamaterials.