An Analysis of Tube Material properties and Tube-Hydroforming Processes
Date Issued
2005
Date
2005
Author(s)
Huang, Jheng-Kai Ciou
DOI
zh-TW
Abstract
The application of tube-hydroforming technology to the parts of lightweight automobile is becoming more and more popular, but its original blank and manufacture processes are different from those in the conventional stamping. So, this paper will discuss the material properties of tubes and the methods of die design.
This paper first discusses the differences of material properties between the plate and the tube by the simulation of tube-making, in order to predict the tube material properties by the dimensions of the tube. In terms of the experimental verification, this paper compares the material properties between the plate and the tube by experimenting on the tubes of different dimensions, including four hot-rolled tubes, one cold-rolled tube, and three stainless tubes. The results of the experiments can be used to establish the predictive formulas of the hot-rolled and stainless tubes. In addition, this paper discusses the Bauschinger Effect on the experimental results. Finally, this paper establishes a process for material tests.
This paper also analyzes the maximum allowable wrinkle of the tube in the preform process and discusses the effect of die shape on the wrinkle of the tube. Another factor that influences the wrinkle is the tube size. When the tube size is determined, special attention should be paid to the section of the die at the tube expansion rate under 5%, where unexpanded hollowness happens easily. The last step is to improve the hollowness of the tube by different die designs.
In the planning of the hydroforming process, the paper analyzes a representative automobile part to build up the CAE simulation model of tube bending, preforming, and hydroforming, and discusses the influence of different preform designs and bending radii on the final shape of the tube. In this paper, we also compare the simulation results with the actually hydroformed parts. The results show that there is a considerable accuracy of simulation by using the finite element method. The results of this study can be a reference for related academic research and can also be used to develop related products for industry production.
Subjects
液壓成形
最大凹陷量
預成形
hydroforming
Bauschinger Effect
maximum wrinkle
preform
Type
thesis
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