In-plane shear stiffness of diversified hexagonal honeycombs: A simple energy-based approach

The conventional hexagonal honeycomb is widely used in various practical applications. The re-entrant and semi re-entrant hexagonal forms derived from the conventional one have gained large attention in recent years due to their unusual Poisson's ratio and superior mechanical performance. However, the in-plane shear behavior of the semi re-entrant hexagonal honeycomb has not been reported yet. Especially, a comparative study on the shear stiffness of the three hexagonal honeycombs is lacking. A simple energy-based approach was used in this paper to establish theoretical models for predicting the in-plane shear modulus of the hexagonal honeycombs, which were later verified by the numerical simulations. Good agreement between the theoretical and numerical results is observed. The effect of the geometrical parameters on the shear modulus and the specific shear modulus were further discussed. It is found that the conventional hexagonal honeycomb displays higher shear modulus and specific shear modulus than both the re-entrant and semi re-entrant ones, while the re-entrant hexagonal honeycomb demonstrates the lowest values of shear modulus and specific shear modulus