Crushing response of square aluminium tubes filled with polyurethane foam and aluminium honeycomb

Experimental investigations were conducted to study the axial crushing behaviour of square aluminium tubes with different configurations. Quasi-static compressive loads were applied to square hollow aluminium tubes, aluminium honeycomb-filled tubes, polyurethane foam-filled tubes and aluminium tubes filled with both polyurethane foam and aluminium honeycomb at constant velocities of 0.15 mm/s, 1.5 mm/s and 15 mm/s, respectively. The effects of honeycomb core, polyurethane foam, combined polyurethane foam and honeycomb on the axial crushing behaviour of square aluminium tubes were discussed. The influence of crushing velocity on these different tubular structures was also studied. Experimental results showed that the deformation mode was a progressive folding mode for square hollow aluminium tubes, while it was a splitting mode for square tubes filled with both polyurethane foam and aluminium honeycomb. The fold wavelengths of some typical cases were measured. The most crashworthy combination was found to be square aluminium tubes filled with both polyurethane foam and aluminium honeycomb, where the maximum increases of mean crushing force, energy absorption and specific energy absorption were up to 349%, 334% and 109% respectively, compared with those of hollow tubes.