Deformation characteristic of asymmetric channel sections on draw bending process with restriction dies preventing undesirable deformation

Light gauge aluminum alloy extruded sections are advantageous for reducing the weight of any types of structure. A dissymmetrical channel section is a major example. In general, a secondary forming process such as bending is required for actual applications of these materials. However the bending of channel sections causes several types of undesirable deformation such as flattening wrinkling and torsion. There are two methods for preventing undesirable deformation. One is usage of restriction dies, and the other is application of an axial tension. In this study, the draw bending was focused, because application of restriction dies is easy and loading of axial tension is available. As the restriction dies, a laminated mandrel, a wiper die, and plates for preventing torsion were proposed. Finite Element Analysis(FEA)of draw bending was demonstrated to clarify effect of restriction die and axial tension. First, the draw bending was simulated to confirm the effect of the material properties. Next, in order to confirm the effect of the restriction dies and the axial tension against the undesirable deformation, the draw bending was simulated circumstantially. From these results, the effect of the restriction dies and the axial tension was described.