Pattern transformation of single-material and composite periodic cellular structures

Novel pattern transformation occurs when periodic cellular structures are compressed beyond a critical value. We have designed a kind of composite periodic cellular metamaterials with soft matrix and interfacial layers, and the buckling modes phase diagram of the composites is obtained. The buckling behaviors of the composites are studied both in numerical simulations and experiments. It is evident that the critical strains of composite periodic cellular structures are always lower than those of single-material periodic cellular structures, regardless of the interfacial layer is stiffer or softer than the matrix materials. We have proposed a theoretical method to predict the critical strain for the pattern transformation of single-material periodic cellular structures. Furthermore, based on the simulation and experiment results, the theoretical method is developed to predict the critical strain for a definite range of combinations of materials and porosities of the periodic cellular composites.