Dynamic Crushing Behaviors of Second-Order Hexagonal Honeycombs

Hexagonal honeycombs form the common core of composite sandwich structures. In this study, on the basis of the hexagonal honeycomb model, a second-order hexagonal honeycomb is established by cutting pores on the cell wall to realize secondary lightweight design. Furthermore, the in-plane and out-of-plane dynamic crushing behaviors of the second-order hexagonal honeycombs are investigated by combining theoretical analysis with numerical simulation. The effect of the variation in the pore sizes on the cell wall on the in-plane and out-of-plane deformation modes, the mechanical properties, and the energy absorption capacities of second-order hexagonal honeycombs under different impact velocities is discussed. Semi-empirical theoretical formulas for the in-plane and out-of-plane bearing strength of second-order hexagonal honeycombs are proposed. The results show that cutting pores on the cell wall reduces the weights of hexagonal honeycombs and improves their energy absorption capacities. This also provides a new method to realize hexagonal honeycombs that display pore characteristics along both in-plane and out-of-plane directions.