Experimental characterizations of band gaps in 3D printed phononic materials

Abstract

Phononic materials contain spatial periodicity of material properties or geometry, which cause band gaps and other unnatural wave phenomena to form. While these behaviors have been well studied theoretically and experimentally in representative systems, the growth of 3D printing caused a surge of phononic materials to be physically realized and studied in the last several years. Since 3D printing enables almost any geometry to be fabricated in a variety of materials, it opens the possibility for band gaps to be used for frequency-targeted vibration mitigation designed directly into structural components. This talk presents our recent work on 3D printed phononic materials with tailored vibration mitigation, focusing on experimental characterizations of band gaps. Two phononic materials will be discussed: (1) lattice-resonator metastructures, that combine a 3D printed lattice with embedded masses to form band gaps that depend on lattice geometry; and (2) radial phononic materials, that combine radially-dependent properties with periodicity to form band gaps for radially-propagating torsional waves. Experimental intricacies will be highlighted, including material damping, fluid–structure interactions within the band gap, and isolating modes and wave polarizations. Such thorough experimental characterizations of band gaps in phononic materials enable the development of robust and predictive modeling and design capabilities.