Twist Springback of Asymmetric Thin-walled Tube in Mandrel Rotary Draw Bending Process

Abstract

This paper aims to develop an effective numerical model and analyse the twist springback behaviour of asymmetric thin-walled tube in mandrel rotary draw bending. Yld2000-2d anisotropic yield criterion integrated with mixed isotropic and kinematic hardening model was used to describe the material properties including anisotropy and Bauschinger effect. The corresponding mechanical experiments such as uniaxial tension, monotonic and forward-reverse shear tests were performed to obtain the material parameters. A three-dimensional elastic-plastic finite element model was developed, and its validity was assessed by comparing the predicted twist springback with experiment one. Based on the present FE model, the tangential stress distribution during different bending steps were analysed to explore the source of twist springback. The results indicate that the torsion moment of cross sections caused by the non-homogenous stress states play a considerable role in twist springback prediction.