Isolating low-frequency vibration via lightweight embedded metastructures

Load-bearing lightweight structures, such as lattice structures, are commonly used in various engineering fields, but often suffer from environmental low-frequency vibration which is difficult to suppress. The emerging field of metastructure offers a practical solution for the low-frequency vibration reduction without introducing extra isolators that have gigantic size and heavy weight. In this research, 3D printed subwavelength-scale microstructures are embedded into a honeycomb beam to form a lightweight metastructure which can suppress vibrations with different polarizations at targeted frequencies. Moreover, by simply rotating the fabricated resonators from the horizontal embedment into the vertical embedment, the bandgaps as well as the vibration isolations can be easily switched for different vibration sources. The multi-polarization vibration isolations have also been demonstrated with strategically positioned resonators following interval and segment arrangements. Finally, metastructures with geometrically optimized microstructures as well as quasi-zero dynamic stiffness microstructures are designed to achieve an even lower frequency isolation with unaltered lightweight advantages.