تحليل تجربي و عددي فرآيند هيدروفرمينگ لوله با فشار نوساني در قالب جعبه اي شكل

Experimental Study and Numerical study of Pulsating Hydroforming of Tube in Box-Shaped Die

In recent years, the hydroforming has attracted the attention of the automotive industry due to reduction in weight and increase in strength of automotive parts. Thus, the knowledge of the process to produce parts with desired quality and accuracy has been growing. One of the effective methods in improving the formability in the hydroforming is known as pulsating hydroforming. However, the reason of improvement of the formability in pulsating hydroforming is still unclear for the closed-die hydroforming of tubes. In this study, the pulsating hydroforming of tube with box die was simulated by the finite element method to examine the effect of pulsating pressure on improvement of formability. In addition, the calculated results are compared with experimental results and it is shown that the improvement of the formability occurs before contact of the tube and die in expansion zone of the tube. Thus, it can be obtained from the results, that the main reason of improvement of the formability is due to the deformation behavior before start of contact of the tube and die. Flat bulging appears for the pulsating pressure in the former stage, whereas round bulging and wrinkling occur for the high and low non-pulsating pressures, respectively.