带筋管整体成形力学条件研究

Mechanical Conditions of Stiffened Tube during Hydro-assisted Forming

目的掌握带筋管整体成形的工艺条件。方法实验研究了带筋管坯整体成形易出现的缺陷形式,并分析了影响筋板整体成形的力学条件。结果实验结果表明:对于一定高径比范围内的带筋管可整体成形,但当高径比超出临界值时,易发生起皱和倾倒缺陷。起皱主要发正在曲率半径增大的部位,倾倒则发生在曲率半径减小的部位。起皱发生的原因是曲率半径增大导致筋板中性层外侧形成了较大的压应力,倾倒则是非均匀分布的拉应力形成了弯矩,进而导致了失稳的发生。结论带筋管内部施加支撑压力能同时降低压应力和弯矩,避免起皱和倾倒的发生。最终成功成形出了椭圆度为1.5和2的整体带筋管件。

To explore the technological conditions of whole forming for stiffened tube,the defect mode of whole forming for stiffened tube was researched and the mechanical conditions for whole forming were analyzed.Experiment results showed that whole forming might be realized for stiffened tube with certain height-diameter ratio;however buckling and wrinkling might happen when the height-diameter ratio exceeded the critical value.Wrinkling mainly happened on the location where radius of curvature was increased and buckling happened on the location where radius of curvature was decreased.Compressive stress state that was caused by increased radius of curvature was the main mechanical reason for wrinkling defect.Bending moment that was caused by unevenly distributed tensile stress was the main reason for buckling defect.In conclusion,internal pressure is useful to decrease the stress and bending moment and prevent wrinkling and buckling.At last an integral stiffened tube component can be formed with ovality at 1.5 and 2.