An Analytical Model for Long Tube Hydroforming in a Square Cross-Section Die Considering Anisotropic Effects of the Material

In this paper, a mathematical model was developed to analyze the hydroforming process of a long anisotropic circular tube into a square cross-section die. By using the thickness variation in two extreme cases of friction between the tube and die wall, namely no friction and sticking friction cases, thickness variation in the case of sticking friction was captured in the model. Then by using equilibrium equation for contact length segment, thickness distribution was determined and corresponding forming pressure is predicted. It was shown that in a plane strain state, anisotropic value has no influence on thickness variation of the deformed tube and the forming pressure will increase when the anisotropic value increases. The analytical results of forming pressures and thickness distributions were compared with the results available in the literature to verify the validity of this simple analytical proposed model.