Six-axis free bending and twisting analysis of spiral square tube

Abstract

Six-axis free bending and twisting (6FBT) technology enables the integral forming of square tube components with complex shapes. However, the process analysis method and the deformation behavior of square tube spiral components in the bending and twisting process have not been investigated. In this paper, an analytical model of the bending die trajectory suitable for one-time forming of square tube spiral components is proposed and verified by FE simulations and experiments. In this model, the bending direction of the component axis is changed continuously by adding an additional cross section torsion angle in the bending process of the square tube, and then the spiral member is formed. This paper further reveals the laws of stress, strain, wall thickness distribution and cross section distortion of 304 stainless steel square tube spiral components in the 6FBT process. The results show that during the forming process, the equivalent stress on the edge of the square tube is greater than that on the surface, the wall thickness reduction on each cross section only occurs on the outside of the bent, and the section distortion between the inside and outside of the bent is larger than that between the inside and outside of the twist.