Pentamodes are lattice structures composed of beams. Their main property is the low ratio of the shear to bulk modulus, making them suitable for aerospace, antiseismic, and bioengineering applications. At first, in our study, pentamode structures were fabricated using three-dimensional printing and were tested in a laboratory. Then, computational analyses of bulk strength have been performed. In addition, several preliminary computational analyses have been considered, comparing different pentamodes’ dimensions and topologies in order to understand their behaviour under different loading conditions. Experimental results have been compared with the numerical results in order to validate the forces applied to the lattice structures. Our new contribution is that for the first time, the experimental and numerical results are investigated up to the failure of the specimens, the effective Young’s modulus has been calculated for different pentamode lattice structures, and our results are also compared with analytical equations.

Mechanical metamaterials are lattice structures that are analysed to be used in modern engineering applications. Pentamodes structures are designed to confront high compressive loads. Due to their wide field of applications, several different structures can be produced, and especially with variable height. Thus, the buckling behaviour of such structures should be analysed, to better understand their characteristics. In our computational analyses two types of pentamodes structures have been considered, with and without confinement plates. In addition, two pentamode beams thickness have been considered. By varying the height of the pentamodes, the results show a correlation between beam’s thickness and effective Young’s modulus. Also, for the first time it is shown that the height of pentamode structures is a significant factor to the results for the effective Young’s modulus. Finally, the first eigen buckling forces in linear buckling analyses are presented, which relate the eigen buckling forces to pentamodes’ height and beam’s thickness.