Preform Design for Tube Hydroforming Based on Wrinkle Formation

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Chen Yang ◽  
Gracious Ngaile
Keyword(s):  
Circular Cylinder ◽  
Axial Compression ◽  
Process Design ◽  
Tube Hydroforming ◽  
Preform Design ◽  
Two Stage ◽  
Evolution Characteristics ◽  
Hydroforming Process ◽  
Ss 304 ◽  
Thinning Rate

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.

Corner Fill Modeling of Tube Hydroforming

2000 ◽  
Author(s):  
J. Y. Chen ◽  
Z. C. Xia ◽  
S. C. Tang
Keyword(s):  
Numerical Experiment ◽  
Internal Pressure ◽  
Process Design ◽  
Tube Hydroforming ◽  
Design Guidelines ◽  
Structural Components ◽  
Round Tube ◽  
Fundamental Understanding ◽  
Hydroforming Process ◽  
Square Box

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.

Preform Design for Formability Enhancement of Tube Hydroforming Process Using Deformation History

2007 ◽  
Vol 340-341 ◽  
pp. 593-598
Author(s):  
Woo Jin Song ◽  
Han Ho Choi ◽  
Keun Hwan Kim ◽  
Sung Ho Park ◽  
Jeong Kim ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Production Cost ◽  
General Procedure ◽  
Tube Hydroforming ◽  
Numerical Approach ◽  
Preform Design ◽  
Trial And Error ◽  
Deformation History ◽  
Optimum Configuration ◽  
Hydroforming Process

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.

Tribological Issues in the Tube Hydroforming Process—Selection of a Lubricant for Robust Process Conditions for an Automotive Structural Frame Part

2003 ◽  
Vol 125 (3) ◽  
pp. 484-492 ◽  
Author(s):  
Muammer Koc¸
Keyword(s):  
Process Design ◽  
Tube Hydroforming ◽  
Process Conditions ◽  
Process Selection ◽  
The Coefficient Of Friction ◽  
Hydroforming Process ◽  
Critical Regions ◽  
Robust Process ◽  
Lubricant Performance ◽  
Selection Of

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.

scholarly journals Effect of heat treatment temperatures on formability of SS 304 during tube hydroforming process

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
P. Venkateshwar Reddy ◽  
B. Veerabhadra Reddy ◽  
P. Janaki Ramulu
Keyword(s):  
Heat Treatment ◽  
Tube Hydroforming ◽  
Hydroforming Process ◽  
Ss 304
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