A Comparison between cutting and folding modes of an extruded aluminum alloy tube during impact using ductile failure criterion

Abstract

Thin-walled structures like crash boxes may be used as energy absorbers in the automotive chassis. There have been lots of investigations about the behavior of these parts during frontal crashes. Previous researches show that thin-walled circular tube has the highest energy absorption among different structures. In this study, cutting and folding modes of extruded aluminum tubes (EN-7018 T6) with 50 mm diameter, lengths of 300 and 400 mm and thicknesses of 2, 2.5 and 3 mm are compared when axial impacts with velocities of 6, 8 and 10 m.s-1 are applied to them. Cutting tools of 4 and 6 blades are used to provide the cutting mode. Effective parameters of energy absorbers including crush force efficiency, specific energy absorption and maximum axial load are modeled numerically with the help of Hooputra’s ductile damage criterion and are compared to each other for three cases of aluminum tube folding between two rigid plates and tube rupture by using 4 and 6 blades cutting tools. The analyses show that the tube rupture by the 6 blades cutting tool is better than the other two in the case of energy absorption. Furthermore, the results demonstrate that tube cutting with the help of multi-blades cutting tools is more stable, controllable and predictable than tube folding.