A design of active elastic metamaterials with negative mass density and tunable bulk modulus

This article details the molecular modeling of full and off-stoichiometry models of the DGEBF/DETDA epoxy system using Molecular Dynamics to predict the mechanical properties as a function of the crosslinking density. The Reactive Interface Force Field (IFF-R) is implemented in this work to simulate mechanical deformation. The “fix bond/react” command in LAMMPS is used to simulate crosslinking between epoxy monomers. The results show that the predicted mass density, volumetric shrinkage, and bulk modulus have a strong dependence on the stoichiometry of the epoxy.

Download Full-text

Modelling of elastic metamaterials with negative mass and modulus based on translational resonance

International Journal of Solids and Structures ◽

10.1016/j.ijsolstr.2018.12.015 ◽

2019 ◽

Vol 162 ◽

pp. 271-284 ◽

Cited By ~ 11

Author(s):

Zhengwei Li ◽

Chen Wang ◽

Xiaodong Wang

Keyword(s):

Negative Mass ◽

Elastic Metamaterials

Download Full-text

Silicon Pillars as Resonators in an Acoustical Metamaterial

Volume 13: Vibration, Acoustics and Wave Propagation ◽

10.1115/imece2014-37914 ◽

2014 ◽

Author(s):

Bernard Bonello ◽

Rémi Marchal ◽

Rayisa Moiseyenko ◽

Yan Pennec ◽

Bahram Djafari-Rouhani ◽

...

Keyword(s):

Thin Plate ◽

Lamb Waves ◽

Mass Density ◽

Resonant Mode ◽

Ultrasonic Technique ◽

Frequency Range ◽

Negative Mass ◽

Laser Ultrasonic ◽

Compressional Mode ◽

Bending Modes

We have investigated the propagation of Lamb waves in structures made of either an isolated resonant pillar or a set of pillars arranged in a line on a thin plate. The resonators as well as the plate are made of silicon. FEM computations show that two bending modes and one compressional mode are unambiguously identified in the frequency range of interest (0–10 MHz). We used a laser ultrasonic technique to map both the amplitude and the phase of the normal displacements on top of the pillars and at the surface of the sample. When the frequency is tuned to a resonant mode, either compressional or bending, the pillars vibrate 180° out-of-phase with respect to the Lamb waves, resulting in a negative modulus or negative mass density respectively.

Download Full-text

Metamaterial with Simultaneously Negative Bulk Modulus and Mass Density

Physical Review Letters ◽

10.1103/physrevlett.99.093904 ◽

2007 ◽

Vol 99 (9) ◽

Cited By ~ 333

Author(s):

Yiqun Ding ◽

Zhengyou Liu ◽

Chunyin Qiu ◽

Jing Shi

Keyword(s):

Bulk Modulus ◽

Mass Density

Download Full-text