Electroplastic Modeling of Bending Stainless Steel Sheet Metal Using Energy Methods

Abstract

Automotive manufacturers are continuously striving to meet economic demands by designing and manufacturing more efficient and better peiforming vehicles. To aid this effort, many manufacturers are using different design strategies such to reduce the overall size/weight of certain automotive components without compromising strength or durability. Stainless steel is a popular material for .such u.ses (i.e., bumpers and fuel tanks), since it possesses both high strength and ductility, and it is relatively light for its strength. However, with current forming processes (e.g., hot working, incremental forming, and superplastic forming), extremely complex components cannot always be easily produced, thus, limiting the potential weighl-.iaving and performance benefits that could be achieved otherwise. Electrically-assisted manufacturing (EAM) is an emerging manufacturing technique that has been proven capable of significantly increasing the formability of many automotive alloys, hence the "electroplastic effect". In this technique, electricity can be applied in many ways (e.g., pulsed, cycled, or continuous) to metals undergoing different types of deformation (e.g., compression, tension, and bending). When applied, the electricity lowers the required deformation forces, increases part displacement or elongation and can reduce or eliminate springback in formed parts. Within this study, the effects of EAM on the bending of 304 Stainless Steel sheet metal will be characterized and modeled for different die widths and electrical flux densities. In previous works, EAM has proven to be highly successful on this particular material. Comparison of three-point bending force profiles for nonelectrical baseline tests and various EAM tests will help to illustrate electricity's effectiveness. An electroplastic bending coefficient will be introduced and used for modeling an electrically-assisted (EA) bending process. Additionally, the springback reductions attained from EAM will be quantified and compared. From this work, a better overall understanding of the effects and benefits of EAM on bending processes will be explained.

Effect of pulsed current on the deformation behavior of AZ31B magnesium alloy

“…Although the relatively high deformation temperature greatly improves the plasticity of magnesium alloy, hot deformation has many drawbacks such as the increase of thermal stress, the coarse surface, the high expense of energy, the weak dimensional accuracy and the decreased strength of the die [1,3] etc. Then, electrically-assisted forming is considered as an alternative and more excellent processing due to the extra effect of current called electroplasticity effect, which reduces the stress and improves the formability of workpieces [1][2][3][4].…”

A thermal-based approach for determining electroplastic characteristics

“…where P e is the electric power ( I.V ), η is the efficiency, and ξ is the EEC. 2,19 P hea t represents the amount of electric power that will dissipate into heat through resistive heating of the workpiece. P def is the electrical power component that will aid the plastic deformation.…”

“…This coefficient designates the specific efficiency of the electricity used to enhance deformation. In Salandro et al, 19 a similar modeling approach was used to model an electrically assisted air bending process. Since pulsing the electricity is most effective in tension-based processes, a piece-wise model was used to simulate pulsing the current.…”

Withdrawn

“…This particular type of predictions will help to reduce big computational period entering computer simulations. It might be managed while by beginner in FCA [31].…”