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Hydroforming of tubular materials at various temperatures

Aue-u-lan, Yingyot
http://rave.ohiolink.edu/etdc/view?acc_num=osu1167627628

Abstract Details

2007, Doctor of Philosophy, Ohio State University, Industrial and Systems Engineering.
This dissertation research covered two main areas in tube hydroforming process. The first was to develop the methodology to determine the flow stress directly from the tube at room temperature. The hydraulic bulge test was selected for this purpose. The analytical model based on an incremental strain theory was used to predict the wall thickness at the apex of the dome. The thickness predictions were compared with the measured data. The agreement was good. The application of the hydraulic bulge test was extended for use as a tool for a quality control of incoming tubular materials. The experiments were performed to investigate the variations in formability of the tubes produced by roll forming process. The maximum bulge height at the bursting pressure was found to be the most sensitive variable. The second portion of this research was to develop a prototype tube hydroforming system that could be used to form lightweight alloy tubes (aluminum and magnesium alloys) at elevated temperatures. The existing knowledge on process development for forming these materials at the elevated temperature was not sufficient. Therefore, a new design approach, called “submerged concept”, was developed to reduce the heating and filling time and maintain uniform temperature in the tube during hydroforming. The system was used to investigate the effect of the tube extrusion processes (with mandrel –seamless and with porthole die –with seams) on the quality of tubes. Seamless extruded tubes were studied extensively regarding the effect of the process parameters (forming temperatures and forming rates) on the formability and loading behavior. The tubes with seams were found to have defects at the welding line that caused fracture during hydroforming. The results indicated that formability increases with increasing temperature. The forming pressure dropped before the tube touched the die surface, indicating of strain softening. Tensile test was used to obtain the flow stress of the tubes at different temperatures and strain rates. These flow stress data were used in Finite Element simulations to predict process variables, i.e. pressure and axial feed versus time. The comparison between the simulation and experimental results showed reasonable agreement.
Taylan Altan (Advisor)
244 p.
Hydroforming; Tube Hydroforming; Warm Tube Hydroforming; Tubular Materials; Flow Stress

Recommended Citations

Citations

  • Aue-u-lan, Y. (2007). Hydroforming of tubular materials at various temperatures [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1167627628

    APA Style (7th edition)

  • Aue-u-lan, Yingyot. Hydroforming of tubular materials at various temperatures. 2007. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1167627628.

    MLA Style (8th edition)

  • Aue-u-lan, Yingyot. "Hydroforming of tubular materials at various temperatures." Doctoral dissertation, Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1167627628

    Chicago Manual of Style (17th edition)

osu1167627628
3,118
© 2006, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.