Pentamode metamaterials with independently tailored bulk modulus and mass density

TL;DR

This paper introduces a new class of 3D elastic metamaterials that allow independent tuning of bulk modulus and mass density, enabling customized mechanical properties for advanced applications.

Contribution

It presents a systematic evaluation of static and dynamic properties, including fabrication of polymer microstructures and analysis of layered laminates with anisotropic mass density.

Findings

Effective parameters can be independently adjusted over a large range.

Static and dynamic properties are consistent in the long-wavelength limit.

Laminates exhibit anisotropic uniaxial dynamic mass density tensors.

Abstract

We propose a class of linear elastic three-dimensional metamaterials for which the effective parameters bulk modulus and mass density can be adjusted independently over a large range|which is not possible for ordinary materials. First, we systematically evaluate the static mechanical properties and the phonon dispersion relations. We show that the two are quantitatively consistent in the long-wavelength limit. To demonstrate the feasibility, corresponding fabricated polymer microstructures are presented. Finally, we discuss calculations for laminates composed of alternating layers of two different metamaterials with equal bulk modulus yet different mass density. This leads to metamaterials with effectively anisotropic uniaxial dynamic mass density tensors.