Investigation of the Effects of the Coil Design on Electro-Magnetic Forming of a Thin-Walled Aluminum Tubular Material

In this study, a thin-walled aluminum tube was expanded using the electro-magnetic forming (EMF) process. Two different designs of coil were developed using EMF simulations with LS-DYNA's electromagnetic module in version 980. The initial thickness of the aluminum tube was 0.254 mm (0.01 in.) and the material of the tube was Aluminum 3000 (Al-3000). This aluminum material is known to be difficult to expand more than a 9% expansion ratio at a given thickness. To evaluate the performance of the coil to expand the tube without failures, two different coils were designed and manufactured to have two different gaps between the coil and the workpiece. Preliminary simulations were conducted to determine the baseline design of the coil and after some preliminary EMF tests, the coil design was changed. Tubular samples were tested with two different coils and two different die sets (e.g., 10 and 12% expansion ratios). The EMF process was numerically modeled with LS-DYNA and the simulation results were compared with experiments.