1Mechanical Engineering Department, Islamic Azad University, Shiraz, Iran
2Mechanical Engineering Department, Islamic Azad university, Shiraz - Iran
Abstract Hydroforming process is a deep stretching process only with the difference that a fluid is used instead of the mandrel. This paper investigates the hydroforming process of non-cylindrical and non-spherical geometries using finite element analysis software to calculate the influences of effective process parameters such as the coefficient of friction between the surfaces and the pressure applied during the process. Results of this process simulation indicate that decreasing the friction between surfaces, with an optimum lubrication, can decrease the changes in thickness which is related to sheet heightening this leads to a final product with more uniform thickness and more appropriate strength. On the other hand, it is observed that with pressure change there are very slight changes in the thickness for this geometry which can be neglected. The geometry of the mold also showed a great influence on the final quality of the formed sheet. Keywords: sheet hydroforming, complex geometry, finite element analysis, friction, multistage pressure.
 G. Schieß and H. Lindner, Verfahren zum Herstellen eines Hohlkörpers, Brevet DE 4232 161 A1(1992).
 M. Geiger and F. Vollertsen, Verfahren zum Herstellen von schalenförmingen Hohlstrukturen aus gedoppelten Blechzuschnitten mittels Innenhochdruckum formung Brevet DE 195 35 870 A1(1997).
 D. Schmoeckel and P. Dick, High pressure forming of sheet metal sheets in producing hollow-formed parts, Prod. Eng., Annals of the WGP, 1(1997) 5-8.
 A. Assempour and M. R. Emami, Pressure estimation in the hydroforming process of sheet metal pairs with the method of upper bound analysis, Journal of Materials Processing Technology, 209(2009) 2270–2276.
 M. Geiger, M. Merklein and M. Cojutti, Hydroforming of inhomogeneous sheet pairs with counter pressure, German Academic Society for Production Engineering (WGP), Prod. Eng. Res. Devel. 3(2009) 17–22.
 L. Tang, T. Ze-jun, H. Zhu-bin and Y. Shi-jian, Warm hydroforming of magnesium alloy tube with large expansion ratio, Trans. Nonferrous met. Soc. China (2010).
 M. Tolazzi, Hydroforming applications in automotive: a review, International Journal of Material Forming, 3(2010) 11:307–310.
 L. Wei, L. Gang, C. Xiao-lei, X. Yong-chao and Y. Shi-jian, Formability influenced by process loading path of double sheet hydroforming, Trans. Nonferrous met. Soc. China (2011).
 L. Xin, X. Yong-chao and Y. Shi-jian, Hydro-forming of aluminum alloy complex-shaped components, trans. Nonferrous met. Soc. China (2011).
 L. Wei, C. Yi-zhe, L. Gang and C. Xiao-lei, Welded double sheet hydroforming of complex hollow component, Trans. Nonferrous met. Soc. China (2012).
 G. Ardalan, Design and calculation types of metal molds, Publishing Idea, Tehran (2004).