A New Experimental Technique for Applying Impulse Tension Loading

Abstract

This paper deals with a new experimental technique for applying impulse tension loads. Briefly, the technique is based on the use of pulsed-magnetic-driven tension loading. Electromagnetic forming (EMF) can be quite effective in increasing the forming limits of metal sheets, such as aluminium and magnesium alloys. Yet, why the forming limit is increased is still an open question. One reason for this is the difficulty to let forming proceed on a certain influence monotonically: the main phenomena causing this increase in formability are considered to due to “body force” effect, inertia effect, changes in strain rate sensitivity. In this study, an impulse tension loading setup is presented. “Body force” effect and strain rate, which are known to be the two key factors leading to higher formability, can now be separated freely by our designed device. Reproducible and adjustable loading rate (80s-1~3267s-1) can be achieved by adjusting the discharge voltage and capacitance. The relation between the discharge voltage and strain rate was obtained with the help of finite element calculations and high-camera measurement results. The results of an exploratory experiment carried out on the designed device are presented for aluminum alloy AA5052 sheet. It shows that this technique could be used to study the dynamic response of sheets.