Abstract
Pentamode materials are artificial solids with elastic properties that approximate those of isotropic liquids. The corresponding three-dimensional mechanical metamaterials or ‘meta-liquids’ have recently been fabricated. In contrast to normal liquids, anisotropic meta-liquids are also possible—a prerequisite for realizing many of the envisioned transformation-elastodynamics architectures. Here, we study several possibilities theoretically for introducing intentional anisotropy into three-dimensional pentamode metamaterials. In static continuum mechanics, the transition from anti-auxetic pentamode materials to auxetics is possible. Near this transition, in the dynamic case, approximately uniaxial versions of pentamode metamaterials deliver anisotropic longitudinal-wave phase velocities different by nearly a factor of 10 for realistically accessible microstructure parameters.
Highlights
Panels (b) and (c) illustrate two examples of anisotropic versions of pentamode metamaterials in which P has been moved along the space diagonal. (b) p =
This shifting leads to a reduced crystal symmetry and to more anisotropic wave propagation
At p = 33.3%, we find extrema for both red velocities versus the position of the point P, indicating a special mechanical behavior or a transition at this geometrically special point
Summary
It is clear from the geometry that one can expect a different wave velocity for propagation along the fcc cube’s space diagonal than for directions perpendicular to that axis. For the geometrical structure parameters, we choose the small diameter d = 0.55 μm (see figure 1(a)), the large diameter D = 3 μm and an fcc extended unit cell lattice constant of a constant corresponds Panels (a)–(c) of figure 2 depict calculated band structures for different positions of P on the fcc cube’s space diagonal.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
