Finite element analysis of free expansion of aluminum alloy tube under magnetic pressure

A link between the electromagnetic code, ANSYS/Emag and the structural code, Ls-dyna was developed, and the numerical modeling of electromagnetic forming for aluminum alloy tube expansion was performed by means of them (discharge energy 0.75 kJ). A realistic distribution of magnetic pressure was calculated. The calculated values of displacement along the tube axis and versus time are in very good agreement with the measured ones. The maximum strain rate is 1122 s^-1, which is not large enough to change the constitutive equations of aluminum alloy. With the augment of discharge energy (0.5-1.0 kJ), the relative errors of the maximum deformation increase from 2.93% to 11.4%. Therefore, coupled numerical modeling of the electromagnetic field and the structural field should be performed to investigate the electromagnetic forming with larger deformation.