Switching of deformation modes in soft mechanical metamaterials

Mechanical metamaterials have attracted tremendous interests, owing to their fruitfulness of underlying physics and mechanics as well as diverse potential applications. Conventional soft mechanical metamaterials contain periodic distribution of holes having identical sizes, which can only display one mechanical function. Periodically dispersing a regular pattern of through-holes with two sizes into an elastomer results in metamaterials with more mechanical functions and deformation scenarios. We numerically investigate the deformation behaviors of this type of metamaterials. Switching of modes from the buckling-dominated deformation to a loss-of-instability deformation is emphasized. Replacing the pattern of holes with the same sizes by a pattern of holes with two sizes imposes higher compliance and even loss of negative Poisson’s ratio of the material.