Effects of Reinforcing Rib on Draw Bending of Pipes Examined by Finite Element Method

Abstract

In recent years, thin aluminum alloy extruded pipes have been applied to structural parts, such as automobile space frames, to save energy. If the aluminum pipes could be processed in a greater variety of ways, such as bending, their range of applications would expand. In our previous study, we evaluated the bending of thin extruded square pipes. In the current study, we examined the bending formability of aluminum alloy pipes with reinforcing ribs using the finite element method (FEM). The influence of the reinforcing ribs on the form accuracy of the aluminum pipes in draw bending was investigated. The effective arrangement and thickness of a reinforcing rib was also investigated. As a result, it was clarified that two types of buckling arise for the reinforcing rib. Furthermore, a critical ratio T ¼ t 2 =t 1 (t 1 : the circular portion thickness of pipe; t 2 : the thickness of rib) for controlling buckling and flattening was proposed.