Thermal Response Modeling of Sheet Metals in Uniaxial Tension During Electrically-Assisted Forming

Abstract

For the current practice of improving fuel efficiency and reducing emissions in the automotive sector, it is becoming more common to use low density/high strength materials instead of costly engine/drivetrain technologies. With these materials there are normally many manufacturing difficulties that arise during their incorporation to the vehicle. As a result, new processes which improve the manufacturability of these materials are necessary. This work examines the manufacturing technique of electrically-assisted forming (EAF) where an electrical current is applied to the workpiece during deformation to modify the material's formability. In this work, the thermal response of sheet metal for stationary (i.e., no deformation) and deformation tests using this process are explored and modeled. The results of the model show good agreement for the stationary tests while for the deformation tests, the model predicts that all of the applied electrical current does not generate Joule heating. Thus, this work suggests from the observed response that a portion of the applied current may be directly aiding in deformation (i.e., the electroplastic effect). Additionally, the stress/strain response of Mg AZ31 under tensile forming using EAF is presented and compared to prior experimental work for this material.