Minimal Surface‐Based Materials for Topological Elastic Wave Guiding

Abstract

Materials based on minimal surface geometries have shown superior strength and stiffness at low densities, which makes them promising continuous-based material platforms for a variety of engineering applications. In this work, it is demonstrated how these mechanical properties can be complemented by dynamic functionalities resulting from robust topological guiding of elastic waves at interfaces that are incorporated into the considered material platforms. Starting from the definition of Schwarz P minimal surface, geometric parametrizations are introduced that break spatial symmetry by forming 1D dimerized and 2D hexagonal minimal surface-based materials. Breaking of spatial symmetries produces topologically non-trivial interfaces that support the localization of vibrational modes and the robust propagation of elastic waves along pre-defined paths. These dynamic properties are predicted through numerical simulations and are illustrated by performing vibration and wave propagation experiments on additively manufactured samples. The introduction of symmetry-breaking topological interfaces through parametrizations that modify the geometry of periodic minimal surfaces suggests a new strategy to supplement the load-bearing properties of this class of materials with novel dynamic functionalities.

Nondestructive Imaging of Manufacturing Defects in Microarchitected Materials

“…3D microarchitected materials represent a transformative class of engineered materials with extraordinary, tailored properties unobtainable in their bulk counterparts. , These metamaterials are defined by their intricate microscale and nanoscale geometries. , The introduction of periodic voids and lattices can imbue distinct properties including ultrahigh stiffness, , exceptional energy absorption, , unconventional acoustic dispersion, , and auxeticity . The utility and versatility of these materials has propelled their adoption into commercial applications such as biomedical stents, protective helmets, frequency-selective soundproofing materials, and footwear. , …”

On‐Chip Tightly Confined Guiding and Splitting of Surface Acoustic Waves Using Line Defects in Phononic Crystals

“…[ 26 ] However, only straight waveguiding was demonstrated, leaving arbitrary guiding to be explored. Fully functional waveguides for Lamb waves, a close analogy to surface waves, were however experimentally implemented in different forms including phononic waveguides, [ 27,28 ] suspended beam waveguides, [ 29 ] and coupled‐resonator elastic waveguides. [ 30 ] It is only recent that advances in the field demonstrated the possibility to achieve arbitrary guiding of surface waves.…”

Uncovering and Experimental Realization of Multimodal 3D Topological Metamaterials for Low‐Frequency and Multiband Elastic Wave Control

“…[20] Initial research concerning topological metamaterials focused on the theoretical prediction and experimental demonstration of 0D topological states in 1D mechanical structures (e.g., the wave is localized at a point in a rod) and 1D topological states in 2D mechanical structures (e.g., the wave is localized along a line waveguide in a thin plate). [21][22][23][24][25][26][27][28][29][30][31][32][33] Building upon the promising initial outcomes, researchers have begun to explore beyond the traditional 1D and 2D systems to achieve 2D topological states in 3D structures (e.g., the wave is localized along a planar waveguide in a 3D cubic geometry). To construct 3D topological metamaterials, the elastic analogs of Weyl semimetals or the quantum valley Hall effect (QVHE) from electronic systems have been created by carefully configuring the spatial symmetries of 3D periodic lattice geometries.…”