Comparison Between Experimental and Numerical Results of Electromagnetic Forming Processes

Electromagnetic Forming (EMF) is a high speed metal forming process that is being studied with interest in both academia and industry as a way of improving existing sheet metal forming. The main thrust of the published research has been increasing the formability of aluminum alloys. Observing and measuring EMF process is made very difficult by the high speeds involved and the tooling used to obtain the final shapes. As with many other processes, numerical simulations can potentially be used to study the details of EMF; however, one limiting factor is the difficulty in modeling the process, since accurate models of both the structural and electromagnetic phenomena must be solved. Researchers have relied on simplifications that use analytical magnetic force distributions, on separate electromagnetic (EM) and structural codes or on in-house codes that can solve both problems simultaneously. In this paper, the predictive ability of the EM module of LS-DYNA® is assessed through a comparison between experimental and numerical results for samples formed by EMF. V-Channel and conical shaped samples were formed using two different EMF apparatuses. For the V-Channel samples a double rectangular coil was used and for the conical samples a spiral coil was used. Both processes were modeled using LS-DYNA®’s EM module. A comparison of the final experimental and numerical final shape and current profiles is presented. It was found that the models provide good qualitative results and are able to predict the major features of the samples studied. Good quantitative agreement between the predicted and measured current profiles was found. The discrepancies observed are the result of numerical issues and the simplifications used in the creation of the specific models. It was found that the software can accurately predict the trends of the forming processes studied.