Elastic measurements on macroscopic three-dimensional pentamode metamaterials

Abstract

Pentamode metamaterials approximate tailorable artificial liquids. Recently, microscopic versions of these intricate three-dimensional structures have been fabricated, but direct experimental characterization has not been possible yet. Here, using three-dimensional printing, we fabricate macroscopic polymer-based samples with many different combinations of the small connection diameter $d$ and the lattice constant $a$. Direct measurements of the static shear modulus and the Young's modulus reveal that both scale approximately according to $(d/a{)}^3$, in good agreement with continuum-mechanics calculations. For the smallest accessible values of $d/a\approx 1.5\%$, we find derived ratios of bulk modulus $B$ to shear modulus $G$ of $B/G\approx 1000$.

9 pages, 4 figures

References in corpus (6)

• Acoustic cloaking theory
• Achieving control of in-plane elastic waves
• Acoustic metafluids
• Highly-anisotropic elements for acoustic pentamode applications
• Phonon band structures of three-dimensional pentamode metamaterials
• Special transformations for pentamode acoustic cloaking

Cited by in corpus (6)

• On three-dimensional dilational elastic metamaterials
• Bending dominated response of layered mechanical metamaterials alternating pentamode lattices and confinement plates
• Boundary effect on acoustic cloak with unideal pentamode material
• Additively manufactured hybrid anisotropic pentamode metamaterials
• Single-test evaluation of directional elastic properties of anisotropic structured materials
• Near optimal pentamodes as a tool for guiding stress while minimizing compliance in $3d$-printed materials: a complete solution to the weak $G$-closure problem for $3d$-printed materials