Electromagnetic Forming Limit Diagram of AA5182-O Aluminum Alloy Sheet: Marciniak–Kuczynski Model, Simulation and Experiment

The experimental acquisition of electromagnetic forming limit is significantly confined due to the non-uniform pulse pressure of electromagnetic actuator and the complex deformation behavior of sheet metal. Hence, it was proposed to determine the electromagnetic forming limit diagram of aluminum alloy sheet by combining theoretical model, numerical simulation and experimental verification. The Marciniak–Kuczynski model embedded with Cowper-Symonds rate-dependent hardening model was derived in order to consider the strain rate effect on the electromagnetic formability of aluminum alloy sheet. The self-loop samples were newly designed with long oval coil for electromagnetic forming experiments to accomplish the typical deformation paths of uniaxial tension and plane strain. The strain rates and strain paths were investigated by numerical simulations. With the electromagnetic forming limits under uniaxial tension and plane strain conditions, the Marciniak–Kuczynski model was calibrated to fully determine the electromagnetic forming limit diagram. The electromagnetic bulging experiment was carried out to validate the electromagnetic forming limit diagram. Compared with the quasi-static forming limit diagram, the electromagnetic forming limit diagram of AA5182-O aluminum alloy is much higher. The electromagnetic forming limits under uniaxial tension, plane strain and equal-biaxial tension conditions are improved by 43%, 53% and 59%, respectively.