Dynamic axial crushing of origami crash boxes

Thirty-three dynamic tests on thin-walled tubes including conventional square tubes and two types of origami crash boxes were conducted on a drop hammer rig. All of the origami crash boxes have identical thickness t and surface area A to those of conventional square tubes. Experimental results validate that origami crash boxes perform better than the conventional square tubes. And the mean crushing force of origami crash boxes with longer modules (l/t=60) is larger than that with shorter ones (l/t=40). Complete diamond mode as well as two new collapse modes, which are local buckling mode and symmetric mode, were observed in tests. The comparison among those three collapse modes suggests that the complete diamond mode is the most efficient one and the symmetric mode is the most inefficient one in terms of energy absorption. The effect of local buckling on the mean crushing force is presented to analyze the characteristics of those three collapse modes. It is found that the mean crushing force decreases with the increase of the number of buckling points.