بررسي هاي تجربي و عددي پارامترهاي موثر در يك روش جديد هيدروفرمينگ ورق

Experimental and Numerical Investigations of the Effective Parameters in a New Sheet Hydroforming Method

In recent years, several sheet hydroforming methods have been introduced by researchers. Despite the advantages of these methods, they have some limitations. A new sheet hydroforming process was previously introduced by the authors, where in a polyurethane diaphragm is used to control the blank holder force and to reduce wrinkling in the flange area. In this paper, the effect of significant parameters, including pre-bulging and forming pressure was studied by experimental work and by finite element simulation. It was shown that in forming by the proposed die, a much lower pressure was required compared to those in other sheet hydroformings. Moreover, it was concluded that in the new die, pre-bulging does not considerably affect the sheet thickness distribution. It was also illustrated that by increasing the internal pressure, the critical thickness will be transferred from the punch tip area towards the product wall area. Also, the effect of friction coefficient between the punch and the blank was studied numerically and it was shown that increasing the friction coefficient causes improvement in the thickness distribution.