Numerical Investigation of Pentamode Mechanical Metamaterials

Abstract

Pentamodes are part of the metamaterials’ family and their main characteristics are the peculiar properties, not found in nature, as the low ratio of shear strength to bulk strength. In addition, their lattice nature, contribute to anisotropic behaviour of these materials. Their characteristic, to have low ratio of shear strength to bulk strength, makes pentamodes suitable to confront a wide variety of problems in engineering (antiseismic design, aircraft structures, etc.). Several analytical methods are proposed in order to confront pentamodes metamaterials, but due to the complexity in nowadays engineering problems, a computational analysis should be proposed. In this study, a computational analysis is taking place in the case of pentamodes under quasi static conditions. The pentamodes behaviour under small and large displacements analyses for different materials and for different loading conditions have been analysed and investigated. Analytical results are also proposed and compared with those from numerical analyses. From our study it is observed that pentamodes decrease their shear and compression moduli when their height increases. In addition, the ratio of compression to shear modulus appears to coincide for the different material cases considered.