Authors: S.M.H. Seyedkashi, Golam Hosein Liaghat, Hassan Moslemi Naeini, M. Hoseinpour Gollo
Abstract: Tube hydroforming technology is still considered a new technique growing fast in automotive and aircraft industries. Many researches on all aspects of this process are still required. Contact friction is one of the most effective parameters on tube wall thinning. To successfully fulfill the process without any common defects, it is very important to determine the proper internal pressure and axial feeding loading paths. In this paper, the effect of lubrication on tube wall thinning on ASTM C11000 copper alloy is discussed as well as the effect of internal pressure and axial feeding. An axisymmetric bulged tube is investigated using theoretical, numerical and experimental methods. Improved linear and non-linear pressure and feeding loading paths are applied and the predicted results are experimentally proved. It is observed that non-linear pressure application gives smoother results. Also proper lubrication plays an important role in success of the process.
133
Authors: Xun Zhong Guo, Jie Tao, Zheng Yuan
Abstract: The hydroforming process to manufacture Al 5083 T-shapes with desired protrusion height and uniform thinning rate was evaluated by means of numerical simulation in this work. The optimization of process parameters and the prediction of forming effect were then carried out. Subsequently, the practical forming was performed based on the simulation results. It was obvious that the simulation results agreed well with the experimental ones. In addition, the streamline on the surface which formed in the hydroforming process was observed in the experiment.
2668
Authors: Mohsen Loh-Mousavi, Amir Masoud Mirhosseini, Ghasem Amirian
Abstract: In recent years, tube hydroforming has been applied in automobile and airplane industries, to decrease weight. In general, the determination of internal pressure path is a key factor in improving the formability in tube hydroforming. One of the effective methods in improving the tube hydroforming is using the pulsating internal pressure path. In this research, hydroforming of bi-layered tubes under pulsating pressure in x-shaped die is simulated by means of three dimensional finite element method. Some numerical results were compared with experimental results and show good correlation. Influence of pulsating pressure on the thickness and stress distribution have been also studied. It was shown that pulsating pressure improves the formability in hydroforming of bi-layered tubes via continues and gradual removing returnable wrinkling which is caused by a low pressure in this process. In addition, effect of some key parameters such as friction and die corner filling have been investigated.
5
Authors: Cheng Zhan Chen, Yi Gan, Ji Tao Du, Can Huang, Qi Jun Chen
Abstract: The finite element software DYNAFORM was applied to simulate the whole tube hydroforming process. Two main failure types in the process of hydroforming are wrinkling and bursting. The strain distribution and thickness distribution at different process parameters were presented. Not only friction coefficient but also the effect of different matching of internal pressure and axial force was simulated and analyzed. In addition, the velocity of punch was considered too. The result has reference value for the variable cross-section tube hydroforming process research.
901
Authors: Wen Liu, Ji Qiang Li, Bin Bin Chen, Zhi Xin Jia
Abstract: Based on the analysis of now available evaluation indexes to estimate the formability of T-shaped tube hydroforming, an aggregative indicator is proposed. The effect of load path on the formability of T-shaped tube is discussed by FEM simulation, and validity of the evaluation index and simulations are proved by experiment. Results show that with the broken line load path of 0-35-35-60, the value of aggregative indicator is the greatest and the formability is the best. The optional parameters are testified by experiment and the results are in agreement with the FEM simulation results.
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