X.S. Wang
,
S.J. Yuan
,
X.R. Huang
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
The tube hydroforming process for manufacturing the tubular part with large perimeter difference was studied by means of experiments and FE simulation. It is an asymmetrical one and the expansion ratio is 70 percent. The part is successfully hydroformed by applying the useful wrinkles to accumulate sufficient metal in the area with large
expansion ratio. The thickness distribution is analyzed, and the maximum thinning
ratio of the part is 21.6 percent. It is shown from the experiment and simulation
results that the tubular part with large perimeter difference, long expansion area and
asymmetrical shape can be obtained in one step, applying the useful wrinkles. Typical failure modes were analyzed.
关键词:
Hydroforming
,
Large
,
expansion
,
Useful
,
wrin
Lihui LANG
,
Joachim DANCKERT
,
Karl Brian NIELSEN
材料科学技术（英）
The hydrodynamic deep drawing process enables net shape or near net shape forming of complicated sheet metal parts made from difficultly forming materials, such as aluminium or high strength steels. Based on the conventional hydrodynamic deep drawing process, a new process, hydrodynamic deep drawing process, in which radial pressure is applied to the rim of the blank, is proposed. This new process has been analysed using FEM simulations and the obtained results have been compared with the experimental results. The material used in the experiments was Al-Mg-Si alloy, and in the FEM-simulations the elastic-plastic behaviour of Al-Mg-Si alloy was modelled using Barlat's 89 yield criteria.
关键词:
Hydroforming
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null
,
null
,
null
Shijian YUAN
,
Gang LIU
,
Xianwei TIAN
,
Z.R.WANG
材料科学技术（英）
In order to reduce high calibration pressure in hydroforming of components with too small radii, a method was proposed to manufacture automotive hollow components with rectangular shape by relatively lower pressure. The process is simulated and analyzed. It is thought that the friction force between the die surface and tube is a main reason that high pressure is needed to form small radii. Using the method proposed in this paper, a petal-like section shape is first preformed so that the central zones of the four sides of the preform section do not contact with the die sides, thus the tube metal is easy to flow into the transition radii area in calibration stage. Moreover, a positive force along the sides is produced by the internal pressure, which is beneficial to overcome the friction force and push the material into the radii. Therefore, the pressure for forming the transition radii is greatly reduced and the components with small radii can be formed with relatively lower pressure. For the experimental case conducted in this paper, the forming pressure is reduced by about 28.6% than the estimated forming pressure.
关键词:
Hydroforming
,
null
,
null
,
null
Gang LIU
,
Xuelian YIN
,
Shijian YUAN
材料科学技术（英）
Buckling and forming processes of tubes with varying slenderness ratio (ratio of length to diameter) under external hydraulic pressure were analyzed with three-dimensional finite element method (FEM) for studying tube external pressure forming (EPF). Buckling pressures for different tube blanks without mandrel were predicted, and an EPF of a carbon steel tube onto a mandrel with six ribs was simulated. Both thickness distribution and buckling pressure from the simulations were found to be in agreement with those from experiments. Buckling pressures are shown to be a function of the slenderness ratio. The tubular part with six ribs produced by EPF has a uniform thickness distribution, whose maximum thinning rate is only 5.9%.
关键词:
External pressure forming
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null
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null
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null
