Effect of cell-wall angle on the in-plane crushing behaviour of hexagonal honeycombs

The dynamic crushing behaviors in the x- and the y-directions of hexagonal honeycombs with various cell-wall angles are explored by both experiments and numerical simulations. Several deformation modes are identified based on the shape of the localization band forming by the cells’ collapse. The respective influence of the cell-wall angle, the crushing velocity and the honeycomb’s relative density on the honeycomb’s mechanical properties is studied. It is shown that these influencing factors affect the honeycomb’s x-directional crushing strength by altering the deformation mode of the honeycomb, while both the y-directional crushing strength and the average crushing strength are dominated by the honeycomb’s density. With retaining the honeycombs’ relative density as a constant, the honeycomb with the cell-wall angle of about 45° exhibits the optimal crushing strength and energy absorption capacity under the y-directional crushing, while the average crushing strength in the x- and the y-directions decreases with the cell-wall angle. Significant orthotropic anisotropy is revealed in the honeycombs with the cell-wall angle greater than 30°, especially under low-velocity compression. The honeycomb with the cell-wall angle of about 25° possesses transversely isotropic mechanical properties.

► Cells’ geometry configuration is a non-negligible influencing factor.
► Increasing the crushing velocity will weaken the effect of the cell-wall angle.
► Increasing the crushing velocity will strengthen the effect of relative density.
► The optimal angle for the honeycombs under the y-directional impact is found.
► A transversely isotropic honeycomb is discovered based on the numerical results.