Multi-stable mechanical metamaterials with shape-reconfiguration and zero Poisson's ratio

We investigate the mechanical response of elastic solids perforated with double-U array of parallel fine crack, which leaves tailored mechanical metamaterials containing repeated snapping units with programmed tensile behavior. Our results indicate that under uniaxial tension the metamaterials undergo a large extension caused by buckling snap-through instabilities, and exhibit very small transverse deformation. We find that by largely stretching the pre-cracked specimens, nonlinear mechanical responses including self-recovering snapping and multi-stability enabling snapping behaviors can be generated by tuning the relative stiffness of the curved segments. On this basis, topology analysis is carried out to design three-dimensional (3D) multi-stable configurations for practical applications such as shape-reconfigurable tubes as well as variable stiffness and strength material. This work gives rise to the design, analysis and manufacture of zero Poisson's ratio and shape-reconfigurable materials.