The paper introduces a new alternative towards fabrication of auxetic metamaterials (materials with negative Poisson’s ratio) controlled by geometric transformations. These transformations are derived from the theory of small (infinitesimal) elastic deformation superimposed on finite elastic deformations. By using this theory, a cylindrical region filled with initial deformed foam is transforme...

The dynamic responses of honeycomb sandwich panels (HSPs) subjected to in-plane projectile impact were studied by means of explicit nonlinear finite element simulations using LS-DYNA. The HSPs consisted of two identical aluminum alloy face-sheets and an aluminum honeycomb core featuring three types of unit cell configurations (regular, rectangular-shaped, and reentrant hexagons). The ballistic ...

By means of extensive ab initio calculations, a new two-dimensional (2D) atomic material tin selenide monolayer (coined as tinselenidene) is predicted to be a semiconductor with an indirect gap (~1.45 eV) and a high hole mobility (of order 10000 cm(2)V(-1)S(-1)), and will bear an indirect-direct gap transition under a rather low strain (<0.5 GPa). Tinselenidene has a very small Young's modulus ...

In this work, we investigate the deformation mechanism of auxetic hierarchical rotating square systems through a dynamics approach. We show how their deformation behaviour, hence their mechanical properties and final configuration for a given applied load, can be manipulated solely by altering the resistance to rotational motion of the hinges within the system. This provides enhanced tunability...

Man-made and natural auxetic materials and structures exist from the molecularto the microand macroscales, and cover the major classes of materials (metals, ceramics, polymers and composites). There is now considerable interest in the development of these novel materials due to their counter-intuitive behaviour and also because of their potential in applications where the auxetic property itsel...

There has been a recent upsurge in the study of auxetic, or negative Poisson’s ratio, materials that derive functionality from mechanical instabilities of the underlying structure. One of the simplest auxetic designs comprises an elastomeric slab patterned with an array of voids. Under uniaxial compression, the slender ligaments contiguous to the voids buckle cooperatively, resulting in the shr...

Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading vice versa compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, arrowhead geometries. This paper studies unit cell of hexagonal geometry to understand how changing internal angle fillet radius a...

We present Bistable Auxetic Surface Structures , a novel deployable material system based on optimized bistable auxetic cells. Such structure can be flat-fabricated from elastic sheet material, then deployed towards desired double-curved target shape by activating the mechanism of its component A unique feature is that model design in stable state. This facilitates deployment without need compl...