Effect of thickness and energy on electromagnetic compression of AA6061 tube

Abstract

Electromagnetic forming (EMF) has many applications in the automobile, structural, and other related areas due to its advantages such as reduced springback, wrinkling, and enhanced formability of deformed parts. Deformation of the workpiece depends on various process parameters such as applied energy level; system parameters such as inductance, capacitance, and resistance; and workpiece geometry such as thickness, and shape. These parameters control the current pulse, magnetic field, and Lorentz force. In the present study, effects of workpiece thickness, applied energy level, and process parameters on the deformation behavior of an AA6061 Al tube were studied. An attempt was also made to correlate discharge energy and process parameters with tube deformation. Finite-element (FE) analysis was performed to validate the experimental results. Various parameters such as the Lorentz force, magnetic field, and current density across the workpiece (tube), which cannot be measured experimentally, were numerically computed and correlated with the resulting nature of tube deformation. Aluminum alloy (AA) 6061 tubes with wall thicknesses of 1, 1.7, and 2.4 mm were deformed using a 4-turn bitter copper coil connected to a 40 kJ capacitor bank. In the present case, the intermediate wall thickness of the workpiece showed a higher efficiency for deformation. Moreover, reasonably good agreement was observed between the experimental and FE-simulated results.