Hydro-joining is composed of hydro-piercing, hole flanging and nut-inlaying processes. In this study, a new hydro-flanging process combining hydro-piercing and hydro-flanging is proposed. An internal pressured fluid is used as the supporting medium instead of a rigid die. Three kinds of punch head shapes are designed to explore the thickness distribution of the flanged tube and the fluid leakage effects between the punch head and the flanged tube in the hydro-flanging process. A finite element code DEFORM 3D is used to simulate the tube material deformation behavior and to investigate the formability of the hydro-flanging processes of aluminum alloy tubes. The effects of various forming parameters, such as punch shapes, internal pressure, die hole diameter, etc., on the hydro-flanged tube thickness distributions are discussed. Hydro-flanging experiments are also carried out. The die hole radius is designed to make the maximum internal forming pressure needed smaller than 70 MPa, so that a general hydraulic power unit can be used to implement the proposed hole flanging experiments. The flanged thickness distributions are compared with simulation results to verify the validity of the proposed models and the designed punch head shapes.

中文翻译：

---

铝合金管法兰翻边工艺中冲头形状及加载路径设计的研究

水力连接由水力打孔，翻边和镶嵌螺母组成。在这项研究中，提出了一种新的水力翻边工艺，将水力冲孔和水力翻边相结合。内部压力流体用作支撑介质，而不是使用刚性模具。设计了三种冲头形状，以研究法兰盘管的厚度分布以及在液压翻边过程中冲头和法兰盘之间的流体泄漏效应。有限元代码DEFORM 3D用于模拟管材的变形行为，并研究铝合金管的液压翻边工艺的可成形性。讨论了各种成形参数，例如冲头形状，内部压力，模孔直径等，对液压法兰管厚度分布的影响。还进行了水力翻边实验。模具孔的半径设计为使所需的最大内部成型压力小于70 MPa，因此可以使用通用液压动力装置进行建议的孔翻边实验。将法兰厚度分布与仿真结果进行比较，以验证所提出的模型和设计的冲头形状的有效性。