Numerical study on deformation behaviors of thin-walled tube NC bending with large diameter and small bending radius

摘要

With respect to wrinkling, wall thinning and cross section deformation, combined with analytical description, the deformation behaviors of thin-walled tube NC bending with large diameter D/t (50.0-87.0) and small bending radius Rd/D (1.0-2.0) are explored via a series of reliable 3D-FE models under ABAQUS platform. The results show that: (1) The segmentation feature is observed for the deformation fields such as effective compressive/tensile regions τc / τt, stress/strain distributions, wrinkling tendency, wall thinning and cross section deformation. With smaller Rd/D, the tangent stress increases and becomes more inhomogenous. The maximum tangent stress σφ at the intrados increases by 46% with Rd/D from 2.0 to 1.2. While the distributions of σφ are nearly similar with larger D/t. With smaller Rd/D and larger D/t, the velocity variation of tube materials becomes more obvious. (2) The wrinkling tendency and cross section deformation degree Δ D increase with smaller Rd/D and larger D/t; With smaller Rd/D, both the wall thinning and thickening degrees increase. The maximum wall thinning and thickening degrees increase by 24.0% and 52.5%, respectively. However, with larger D/t, the wall thinning degree increases, while the thickening degree decreases significantly. The maximum wall thinning degree increases by 31.3%, while the maximum thickening one decreases by 58.9%.