Experimental Investigations of Vibration Band Gaps in Platonic 3D Lattice Structures

Vibration band gap structures are advanced materials for vibration wave mitigation from metamaterials to phononic crystals from simple geometrical manipulations. Here, we present geometrical structures, made from platonic solids, that are capable of providing multi-passband frequency ranges with face symmetry in each unit cell. We fabricated the metamaterial structures using stereolithography, after which we experimentally characterized band gaps through impulse vibration testing. Experimental results have shown that the band gaps can be changed for different types of platonic structures along with the loading direction. This provided a comparison between axial and two bending direction band gaps, revealing ranges where the structures behave in either a “fluid-like” or an “optical-like” manner. Dodecahedron unit cells have exhibited the most promising results, when compared with reduced relative densities and a number of stacking unit cells. We utilized the coherence function during signal processing analysis, which provided strong predictions for the band gap frequency ranges.