Corner Fill Modeling of Tube Hydroforming

2000 ◽  
Author(s):  
J. Y. Chen ◽  
Z. C. Xia ◽  
S. C. Tang

Abstract Hydroforming process provides important advantages for automotive structural components over conventional stamp-and-weld parts, but it also brings unique challenges in process design. This paper attempts to obtain fundamental understanding of the process through corner fill modeling. A round tube is pressurized to expand into a square box with tight radius in the numerical experiment. Several parameters are identified and investigated during the process, namely, the internal pressure, end feed, and the lubricant. Their effects on the deformation profiles are presented, and their importance in process design is discussed. The established design guidelines from the study can be a valuable tool for hydroforming process engineers and part designers.

2012 ◽  
Vol 232 ◽  
pp. 537-540
Author(s):  
Xiao Yu Yang

This paper briefly introduces some problems of tube hydroforming process, at the same time, also uses Ansys software to simulate in tube hydroforming process. And draw an conclusion,To avoid defects in tube hydroforming process, the applied internal pressure must be high enough to suppress buckling but not too high to cause bursting.


Author(s):  
Chen Yang ◽  
Gracious Ngaile

A two-stage preforming process based on wrinkle formation is developed for the tube hydroforming process to accumulate material in the forming zone, thus reducing the thinning rate and improving the formability. In preforming stage one, the wrinkle onset is triggered with limited axial compression. In preforming stage two, the wrinkle grows stably and uniformly to a certain height. Then, the preformed wrinkles are flattened to conform to the die shape in the final tube hydroforming process. An analytical model based on bifurcation analysis and postbuckling analysis of the elastic-plastic circular cylinder under axial compression and internal pressure is used to study the wrinkle evolution characteristics in tube hydroforming. The analytical results offer valuable guidance to the process design of the two-stage preforming process. To validate this methodology, preform die sets for two axisymmetric parts were designed and tube hydroforming experiments were carried out on SS 304 tubing. Through this methodology, an expansion rate of 71% was achieved.


2011 ◽  
Vol 473 ◽  
pp. 618-623
Author(s):  
Khalil Khalili ◽  
Seyed Yousef Ahmadi-Brooghani ◽  
Amir Ashrafi

Tube hydroforming process is one of the metal forming processes which uses internal pressure and axial feeding simultaneously to form a tube into the die cavity shape. This process has some advantages such as weight reduction, more strength and better integration of produced parts. In this study, T-shape tube hydroforming was analyzed by experimental and finite element methods. In Experimental method the pulsating pressure technique without counterpunch was used; so that the internal pressure was increased up to a maximum, the axial feeding was then stopped. Consequently, the pressure decreased to a minimum. The sequence was repeated until the part formed to its final shape. The finite element model was also established to compare the experimental results with the FE model. It is shown that the pulsating pressure improves the process in terms of maximum protrusion height obtained. Counterpunch was eliminated as being unnecessary. The results of simulation including thickness distribution and protrusion height were compared to the part produced experimentally. The result of modeling is in good agreement with the experiment. The paper describes the methodology and gives the results of both experiment and modeling.


2007 ◽  
Vol 340-341 ◽  
pp. 593-598
Author(s):  
Woo Jin Song ◽  
Han Ho Choi ◽  
Keun Hwan Kim ◽  
Sung Ho Park ◽  
Jeong Kim ◽  
...  

Preform design in tube hydroforming implies the design of an intermediate shape between initial tube and the final product enabling to be fabricated without defects and excessive loss of material. A carefully selected preform can contribute significantly to reduce production cost and improve formability, since thinned sections may not be able to endure internal pressure during expansion whereas excessive thickening may lead to wrinkles. Generally, preform design in hydroforming was mainly carried out through the trial-and-error approach. Even though a series of numerical simulations for several predetermined preformed shapes were conducted, optimum configuration could not be obtained and could not be suggested the general procedure for preform design as well. In this work, a simple numerical approach to the preform design for formability enhancement was introduced based on the deformation history during forward hydroforming simulation. The proposed approach was implemented to a hydroforming process of an automobile subframe component in order to be satisfied the required specification after hydroforming, and the conceptual application has been proved to be successful on its effectiveness and feasibility. Therefore, it is shown that preform design approach proposed in this study will provide one of feasible methods to satisfy the increasing practical demands for improvement of the formability in hydroforming processes.


2003 ◽  
Vol 125 (3) ◽  
pp. 484-492 ◽  
Author(s):  
Muammer Koc¸

In this paper, an overall review of tribological issues in the tube hydroforming process is presented. Guidelines for the selection of lubricants under the hydroforming process conditions are summarized following a description of existing testing methods and apparatus. A methodology of combined experiments and FEA was presented to determine the coefficient of friction in the hydroforming process in addition to selecting a proper lubricant for a given part and process design. Experimental results showed that thickness of the final part at critical regions, amount of axial feeding and axial force are strong indicators of lubricant performance whereas effect of lubrication on the part flatness, corner radius formation and box dimensions are found to be negligible.


2013 ◽  
Vol 395-396 ◽  
pp. 966-969
Author(s):  
Xue Yi Wang ◽  
Zai Xiang Zheng ◽  
Wen Shan Wang ◽  
Wei Wei Zhang

Due to the apparent advantages of tube hydroforming technology in reducing weight and energy consumption, and saving material and cost, it has been applied in the production of instrument panel beam. By constructing the FEM models of instrument panel beam, three numerical simulation schemes are designed according to the matching relationship between internal pressure load and axial feeding. Then the simulation results are given and compared with the experimental data. The simulation and experimental analysis indicate that the optimal matching relationship between internal pressure load and axial feeding influences hydroforming result of parts. It provides a theoretical reference for the design of hydroforming process and its die, and the setting of critical process parameters.


2007 ◽  
Vol 344 ◽  
pp. 461-467 ◽  
Author(s):  
M. Loh-Mousavi ◽  
Kenichiro Mori ◽  
K. Hayashi ◽  
M. Bakhshi

The filling of the die corner in hydroforming of a tube with a box die was improved by controlling wrinkling under oscillation of internal pressure. In this process, a small wrinkle occurs near the die corner in the former stage, and then the wrinkle is eliminated in the latter stage because the flat bulge appears in the former stage due to the oscillation of internal pressure. A hydroforming process of steel tubes with a box die was performed in both three dimensional finite element simulation and experiment. The filling of the die corner for the mean linear pressure was not sufficient due to large wrinkles appearing in the former stage, whereas bursting occurs for the peak linear pressure due to round bulging. On the other hand, the uniformity of wall thickness of the formed tube was improved by the pulsating pressure.


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