Mechanical behavior of hexagonal honeycombs under low-velocity impact - theory and simulations

Based on the cells' collapse mechanisms of the hexagonal honeycombs revealed from the numerical simulations under the low-velocity impact, an analytical model is established to deduce the crushing strength of the honeycomb and the stress at the supporting end both as functions of impact velocity, cell size, cell-wall angle, and the mechanical properties of the base material. The results show that the honeycomb's crushing strength increases with the impact velocity, while the supporting stress decreases with the increase of the impact velocity. Combining with the dynamic predictions under the high-velocity impact in our previous work (Hu and Yu, 2010), the crushing strength of the honeycombs can be analytically predicted over wide range of crushing velocities. The analytical expression of the critical velocity is also obtained, which offers the boundary for the application of the functions of the honeycomb's crushing strength under the low-velocity and the high-velocity impacts. All of the analytical predictions are in good agreement with the numerical simulation results. (C) 2013 Elsevier Ltd. All rights reserved