Deformation Behavior of Medium-strength TA18 High-pressure Tubes During NC Bending with Different Bending Radii

• Published in: Chinese journal of aeronautics Vol. 24; no. 5; pp. 657 - 664
• Main Authors: JIANG, Zhiqiang, ZHAN, Mei, YANG, He, XU, Xudong, LI, Guangjun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2011
• Subjects: Bending; Deformation; deformation behaviors; finite element method; Mandrels; normal bending radius; Numerical control; numerical control bending; Parabolas; small bending radius; Three dimensional; titanium alloy tubes; Tubes; Wall thickness; 变形行为; 壁厚变化; 弯曲半径; 弯曲角度; 折弯; 数控弯曲; 等强度; 高压管; numerical control bending; finite element method; normal bending radius; small bending radius; titanium alloy tubes; deformation behaviors
• ISSN: 1000-9361
• DOI: 10.1016/S1000-9361(11)60077-0

To improve the forming quality and forming limit of the numerical control （NC） bending of high-pressure titanium alloy tubes, in this study, using three-dimensional （3D） finite element method, deformation behavior of medium-strength TA 18 high-pressure tubes during NC bending with different bending radii is investigated. The results show that the cross-sectional deformation and the wall thickness variation during NC bending of TA18 tubes using a small bending radius （less than 2 times of tube outside diameter） are clearly different from that using a normal bending radius （between 2 and 4 times of tube outside diameter）. For bending with a normal bending radius, with or without a mandrel, the distribution of the flattening in the bending area resembles a platform and an asymmetric parabola, respectively. For bending with a small bending radius, with or without a mandrel, the flattening both distributes like a parabola, but the former has a stable peak which deflects toward the initial bending section, and the latter has a more pronounced peak with a bending angle and deflects slightly toward the bending section. The wall thickness variations with a normal bending radius, with and without a mandrel, both resemble a platform when the bending angle exceeds a certain angle. For the bending with a small radius, the distribution of the wall thickness variation without a mandrel follows an approximate parabola which increases in value as the bending angle increases. If a mandrel is used, the thickening ratio increases from the initial bending section to the bending section.