Numerical and experimental studies on thin-walled aluminum alloy tube hydroforming using differential lubrication method
Numerical and experimental studies on thin-walled aluminum alloy tube hydroforming using differential lubrication method
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DOI：
10.1007/s00339-020-03509-2
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
C. Yuan;Xuefeng Xu;Yubin Fan;Lin Huang
中科院分区：
文献类型：
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作者：
C. Yuan;Xuefeng Xu;Yubin Fan;Lin Huang
分析了T形管液压成形过程中，摩擦系数、内压加载路径和进给加载路径对摩擦力的影响。为此，提出了一种在加载路径设计方法的基础上，通过改变T形管内非对称区域的摩擦系数来调节物料流量的差动润滑方法。对T形管内的差动润滑区域进行了划分，设计了中间半环差动润滑方法。在相同的内压和轴向进给加载路径下，研究了差动润滑和传统的均匀润滑方式对T形管起皱、分支管高度和壁厚分布的影响。同时，对内压和轴向进给不同加载路径下的差动润滑方式进行了仿真。以氟硅脂和PEFT薄膜为润滑介质，对T形管液压成形过程进行了差动润滑实验。仿真和实验结果表明，与传统的均匀润滑方法相比，差动润滑方法更有效地避免了主管后区的起皱，增加了分支管的高度，减弱了增厚。这是提高T形管液压成形成形性能和减少对加载路径依赖的有效途径。
In this paper, it was analyzed that the friction forces that affected the material flow were influenced by the friction coefficient and the load path of internal pressure and feeding in T-shaped tube hydroforming process. Therefore, a novel differential lubrication method was proposed to adjust the material flow through changing the friction coefficient in the asymmetric zone in the T-shaped tube besides the loading path design method. The differential lubrication zones in T-shaped tube were divided, and a method called intermediate semiring differential lubrication was designed. The effects of differential lubrication and traditional uniform lubrication methods on the wrinkle, height of branch tube and wall thickness distribution of the T-tube were investigated under the same loading path of internal pressure and axial feeding. Meanwhile, the differential lubrication methods were also simulated under the different loading paths of the internal pressure and axial feeding. The differential lubrication experiments of T-shaped tubes hydroforming were carried out with fluorosilicone grease and PEFT film as lubrication medium. The simulation and experimental results showed that the differential lubrication method more effectively avoided wrinkles in the back zone of the main tube, increased the height of branch tube and weakened the thickening than the traditional uniform lubrication method. And it was a promising way to improve the formability of T-shaped tube hydroforming and reduced the over-reliance on the loading path.