Ultrasonic bandgaps in 3D-printed periodic ceramic microlattices

Abstract

The transmission of longitudinal ultrasonic waves through periodic ceramic microlattices fabricated by Robocasting was measured in the 2-12MHz frequency range. It was observed that these structures (scaffolds of tetragonal and hexagonal spatial arrangements with periodicity at length-scales of ∼100μm) exhibit well-detectable acoustic band structures with bandgaps. The locations of these gaps at relatively high frequencies were shown to be in close agreement with the predictions of numerical models, especially for tetragonal scaffolds. For hexagonal scaffolds, a mixing between longitudinal and shear polarizations of the propagation modes was observed in the model, which blurred the matching of the calculated band structures with the experimentally measured bandgaps.

Multidimensional Phononic Bandgaps in Three-Dimensional Lattices for Additive Manufacturing

“…Non strut-based AM BG lattices can be seen in the work of Elmadih et al [18] and Abueidda et al [8]; in both these cases, BG structures were obtained using lattices based on triply periodic minimal surface (TPMS) equations. Non strut-based AM BG lattices can also be seen in the ceramic lattice work of Kruisová et al [33] and Ampatzidis et al [17].…”

Anisotropic Elasticity of Ceramic Micro-Scaffolds Fabricated by Robocasting

“…Elastic responses were then calculated by utilizing pure tensile or pure shear straining modes along the principal directions of the unit cells. The density of 3.34 g cm −3 , Young's modulus of 305 GPa, and Poisson's ratio of 0.19 of SiC [6,10] were set as inputs for the calculations.…”

“…Due to their artificial, highly symmetric structure, the fabricated scaffolds exhibit unique acoustic properties, which are not observed in natural materials, e.g. acoustic frequency bandgaps [5][6][7][8][9] and strong acoustic energy focusing [10]. Moreover, such materials can be utilized as light-weight structural materials [11][12][13] or in bone tissue engineering [1,14].…”

Bandgap engineering of three-dimensional phononic crystals in a simple cubic lattice

“…More complex geometries 22 including hollow elements, 23 cellular solids with cubic symmetry, 24 or periodic bicontinuous cubic network structures 25 proved yet unfeasible to fabricate. Only recent advances in additive manufacturing fully opened the third dimension, 26 printing polymer, ceramic, 27 or metal crystals 28 for, e.g., acoustic imaging, 29 vibration isolation, 30 or liquid sensing. 31 This has allowed ultra-wide phononic bandgap materials, 32,33 with previously unattainable bandwidths.…”

“…In the case of a woodpile structure, the largest bandgap of 33% was observed for a tetragonal arrangement with a large spacing. 27 A lattice of simple cubic cube masses connected to a smaller simple cubic lattice of sinusoidal struts yields a theoretical complete bandgap of 89%. 28 The highest similarity to our primary design can be found in a superposition of sphere masses placed in each midpoint of the cube edges with different shapes of connecting beams.…”