Title: Prediction and analysis of wrinkling in tube hydroforming process

Authors: Shijian Yuan, Zejun Tang, Gang Liu

Addresses: National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China. ' National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China; Mechanical and Electrical College, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China. ' National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China

Abstract: Critical stress for the onset of axisymmetric wrinkling in tube hydroforming was derived by separating the wrinkling into the elastic phase and wrinkling phase. The theoretical solution was then validated by the experiment. Moreover, the effects of mechanical properties, stress ratio and geometry on the critical wrinkling stress were analysed and discussed by using this model. It is shown that the theoretical solution is in good agreement with the experiments. Critical wrinkling stress is greater for the tube with higher reduced modulus or higher yielding strength. However, the critical wrinkling stress magnitude of the tube with higher reduced modulus but lower yielding strength should be determined by the relative value between the reduced modulus and yielding strength. If the relative value is greater than zero, the critical wrinkling stress will increase. Besides, critical wrinkling stress will decrease first and then increase as stress ratio increases for longer tubes, but it will increase all along for shorter tubes. Higher ratio of wall thickness to tube diameter will make wrinkles more difficult to produce.

Keywords: tube hydroforming; critical wrinkling stress; stress ratio; mechanical properties; critical stress; axisymmetric wrinkling; wall thickness; tube diameter.

DOI: 10.1504/IJMPT.2011.039937

International Journal of Materials and Product Technology, 2011 Vol.40 No.3/4, pp.296 - 310

Accepted: 21 Feb 2011
Published online: 28 Feb 2015 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article