Springback prediction of three-dimensional variable curvature tube bending

Abstract

The springback phenomenon of tube bending occurs consequentially after unloading, which will affect the manufacturing accuracy and processing efficiency of the tubular products. In this article, the bending and springback processes of minor-diameter thick-walled tube are simulated by ABAQUS to reveal the springback laws. The springback prediction of three-dimensional variable curvature bent tube is projected on each discrete osculating and rectifying plane, and then the three-dimensional problem can be transformed into two dimensions. The mathematic relationship of the radius before and after springback in the plane is built by approximate pure bending springback experiments. The springback on such planes is transformed into three dimensions. The tube axes are merged by first-order geometric (G1) continuity and then compensated with the modified function according to the axis complexity, so as to establish mathematic analytic model for springback prediction of three-dimensional variable curvature tube bending. Finally, the feasibility, reliability, and accuracy of the model are verified by finite element method and experiments.