Numerical Modeling and Experimental Verification for High-Speed Forming of Al5052 with Single Current Pulse

Abstract

Application of electric current pulses during plastic deformation changes the mechanical behavior owing to the electro-plastic effect. The effect of electric current pulses on the Al5052 alloy is investigated in this study. In order to demonstrate the advantages of passing electric current pulses through a metal sheet during the forming process, a uniaxial tensile test with an electric current pulse was carried out using a self-designed device; this device can apply a 2-kA electric current pulse to the specimen for a short period (>100ms). The electric current increases the temperature of the specimen due to Joule heating. It is, therefore, necessary to decouple the thermal effect from the overall behavior to understand only the contribution of electric current in the mechanical behavior. Firstly, an electro-thermo-mechanical finite element study of an electrically assisted uniaxial tensile test of Al5052 alloy is performed to isolate the thermal effect. The simulated results yielded the thermal effect due to the electric current. By comparing the experimental and simulated results, the contribution of electric current is decoupled from that of thermal effect. The electric current-dependent material model is implemented into the commercial FEM code LS-DYNA using user-defined material(UMAT) subroutine. The electric current-dependent material model was used to simulate the electro-mechanical finite element analysis of the high-speed forming of an aluminum sheet with electric current pulse. Simulation results were compared with experimental results at several applied electric currents to evaluate the accuracy of the UMAT. The present work can be utilized to develop simpler constitutive models for the mechanical behavior of metals subjected to a pulsed electric current.

Electrically-assisted deep drawing of 5754 aluminium alloy sheet

“…Only in the case of magnesium alloys the increase of plasticity has been meaningful [24,25]. In the electricallyassisted deep drawing processes, the following problems should still be overcome: excessive heat transfer from the sample to the dies, limited possibility of measuring the temperature or the need to apply higher currents [26][27][28].…”

Numerical Analysis of Experiments on Damage and Fracture Behavior of Differently Preloaded Aluminum Alloy Specimens

“…Ductile fracture can be seen as a major factor causing end of life of structures [3]. Therefore, analysis of deformation, damage, and failure behavior of these newly developed materials is an important concern in engineering disciplines [4]. In this context, development of accurate and practically applicable material models is demanded [5,6].…”