Finite element analysis of electromagnetic bulging of sheet metals

Electromagnetic forming is a high velocity forming technique that uses high pulsed current to produce repulsion electromagnetic pressure between a forming coil and the workpiece. In the FE modelling of such process two physical models are involved; electromagnetic model and mechanical model in addition to a method of coupling these models. Two well-know n coupling schemes were previously used; strong coupling and loose coupling which are either takes long simulation time or gives inaccurate results. Therefore some modifications were made to the loose coupling scheme to give accurate simulation results in small duration.
Material strain hardening models which describe mechanical behaviour of the used material at such high speed forming process are of primary importance to get accurate simulation results. Two hardening models w ere used in previous researches on this process. But no comparison between them was made to conclude the most accurate model in describing hardening behaviour of the used material.

The current investigations introduce a comparison between two hardening material models that used in previous researches. The comparison was made between results of numerical simulations and experimental results obtained from literature. The used FE model is based on modified loose coupling scheme. Simulation results reveal that rate dependant power law hardening model gives the most accurate results with small average deviation compared with experimental data. It reveals also that modified loose coupling between mechanical and electromagnetic aspects is an efficient tool for getting accurate simulation results within short time.