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

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/τtτc/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 σφσφ at the intrados increases by 46% with Rd/D   from 2.0 to 1.2. While the distributions of σφσφ 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 ΔDΔD 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%.