| Project/Area Number |
11650733
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Utsunomiya University |
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Principal Investigator |
FUCHIZAWA Sadakatsu Utsunomiya University, Faculty of Engineering, Professor, 工学部, 教授 (10008039)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAYORI Atsushi Utsunomiya University, Faculty of Engineering, Res.Assoc., 工学部, 助手 (50272216)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Hydroforming / Hydraulic bulging / Thin-walled tube / Deformation characteristics / ハイドロフォーシング |
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| Research Abstract |
First of all, tensile test and hydraulic bulging test were carried out to clarify basic deformation behavior of tubes. The tubes in our study were made of aluminum alloy, copper, steel and titanium. In the hydraulic bulging tests, in-plane stress ratio in the tube specimen was controlled. Summaries of the results are as follows. 1. It is possible to describe their strain hardening behavior using n-th power hardening law. 2. The strain hardening characteristics change depending on the amount of strain. It is roughly divided into two region, small strain region and large strain region. 3. Strain hardening of the titanium tube depends on in-plane stress ratio. The effect of in-plane stress ratio did not appeared in the experimental results with the other materials.
In tube hydroforming, internal pressure and axial feeding are loaded to tube. Tube easily bursts when internal pressure is relatively larger than axial feeding. However, tube buckles when axial feeding is relatively larger than internal pressure. According to our experimental examination, it was clarified that there were two adequate loading methods to achieve large tube expansion without failures. One is the linear loading path where axial feeding is proportional to internal pressure. The other is the bilinear loading path where axial feeding is applied under a constant internal pressure. In the linear loading path, it is possible to find adequate ratio between internal pressure and axial feeding. On the other hand, there is an adequate value of internal pressure in the bilinear loading path.
A model for FEM simulation was constructed and a forming die with square cross section was manufactured to examine the FEM simulation results. Through the FEM simulation and the experiment, it was confirmed that effect of friction between tube and the forming die clearly appeared in distribution of tube wall thickness.
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