RT - Journal Article T1 - Ultrasonic tube hydroforming, a numerical and analytical study JF - mdrsjrns YR - 2013 JO - mdrsjrns VO - 13 IS - 4 UR - http://mme.modares.ac.ir/article-15-4885-en.html SP - 46 EP - 59 K1 - Tube hydroforming K1 - Ultrasonic Vibration K1 - corner filling ratio K1 - uniformity of wall thickness AB - In tube hydroforming process, due to friction condition, uniform wall thickness, as well as sharp corners may not be achieved. Use of ultrasonic vibration can improve the contact conditions at the tube-die interface. The current work studies the effect of applying ultrasonic vibration on wall thickness and corner filling of hydroformed tubes. Firstly, a numerical model based on geometric relationships and stress-strain state has been established by which wall thickness and corner radius of hydroformed tubes can be obtained. In this model, the ultrasonic vibrations affect the nonlinear friction conditions at the tube-die interface. By comparing the FEM models of tubes in two cases of with vibration and without vibration, it is possible to investigate the effects of vibration on wall thickness and corner filling. The results indicate superimposing ultrasonic vibrations to the process will increase corner filling ratio of the tube significantly, and more uniform tube wall thickness will be achieved. LA eng UL http://mme.modares.ac.ir/article-15-4885-en.html M3 ER -