The Compressive and Shear Characteristics of Miura-ori Forms as Core Materials of Sandwich Structures

The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations. The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and shear loading were analyzed using the relative density as a governing parameter. The non-unique relationships between the core density and the materials’ strength in the examined loading directions were revealed, pointing out the strong influence of the Miura-ori topology. Linear relationships were established between the elastic moduli and relative densities of the Miura-ori metamaterials while power-law functions of the relative density with different exponent constants were established for the strength in different loading directions. It was shown that the Miura-ori materials possess the highest strength under shear in the X1- X3 plane and it increases with the increase in the relative density. However, this characteristic is strongly influenced by the sector angle α . In general, the difference between the two shear strengths increases when increasing the relative density by using thicker cell walls. It is noted that the strength of the Miura-ori materials as a function of the relative density is nearly constant with respect to the cell dimensions if the values of folding angle γ and sector angle α are given. The mechanical characteristics of the Miura-ori material with equal relative density, which exhibits the highest strength among the analyzed origami models, are compared with the out-of-plane compression and shear responses of prismatic hexagonal honeycomb. It is observed that compression and shear responses of the honeycomb outperform the Miura-ori foldcore in all loading directions when considering large deformations.