Three-dimensional printing of locally resonant carbon-fiber composite metastructures for attenuation of broadband vibration

This study presents locally resonant acoustic metamaterials made of continuous carbon-fiber-reinforced plastics for vibration attenuation. Unit cells were designed such that the attenuation of low-frequency vibration was compatible with high stiffness. The effect of the path and content of carbon fibers on the band gap was numerically investigated through band-structure analysis for periodic cells. We found that the band gap can be widened by an appropriate placement of carbon fibers in the unit cell. Furthermore, the band gap of the carbon-fiber reinforced metastructures was wider than that of the structures without fibers. Metamaterial samples composed of the designed unit cells were fabricated by 3D printing technique of fiber composites. The vibration transmissibility of the samples was measured and compared with the frequency response function computed by finite-element analysis. The frequency ranges with strong attenuation were in good agreement with those observed in the numerical analysis.